JPH08160699A - Image forming device - Google Patents

Abstract

PURPOSE: To provide an image forming device having a rotary developing device capable of preventing developing units from being dropped by the centrifugal forces applied to the developing units when the developing device is rotated. CONSTITUTION: Multiple developing units 21 storing powder developers are arranged around rotary shafts, and an optional developing unit 21 among multiple developing units 21 is rotated to the development position facing a photoreceptor belt centering on the rotary shaft for development. At least one developing unit 21 among multiple developing units 21 is removably and replaceably provided on the main body of the developing device of a full-color printer. The fitting/removing direction of the developing unit 21 to the main body of the developing device is set to the direction different from the straight line direction connecting the center of the rotary shaft and the center of gravity of the developing unit 21 in the plane perpendicular to the rotary shaft of the developing device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a facsimile or a printer, and more specifically, a plurality of developing devices containing a powder developer are arranged around a rotary shaft. Of any one of the plurality of developing devices, wherein any developing device is rotated about the rotation axis to a developing position facing the latent image carrier to perform development. The present invention relates to an image forming apparatus including a developing device in which a developing device is detachably attached to and replaceable with a developing device main body.

[0002]

2. Description of the Related Art Conventionally, a latent image carrier is exposed with a color-separated light image, each formed latent image is developed with a toner having a complementary color of the color-separated light, and a plurality of obtained toner images are formed on the same transfer paper. Full-color image forming apparatus such as a full-color copying machine that superimposes and transfers the images on the latent image carrier, and the latent images are separately exposed to the images to be reproduced in different colors, and the formed latent images are developed in different colors. 2. Description of the Related Art A multicolor image forming apparatus or the like is known in which a plurality of toner images obtained by developing with a developing agent are superposed and transferred onto the same transfer paper. These image forming apparatuses require a plurality of developing devices for developing a plurality of colors. However, if each developing device is separately configured and installed in parallel around the latent image carrier, the size of the device increases. There was a drawback that it would end up.

Therefore, conventionally, a rotary member is provided so as to be close to the latent image bearing member, and a plurality of developing devices are supported at predetermined positions on the rotary member so that each developing device is supported by the latent image bearing member. Developed and put into practical use a rotary development device that uses a one-component or two-component developer that develops latent images on latent image carriers with toner of each color by sequentially rotating and conveying them to opposite developing positions. Has been converted.

In this type of rotary developing device, the developing device or the developing device is used for replenishment and replacement of toner and developer, maintenance and inspection of the developing device, and replacement of the developing device which has reached the end of its life. It has been proposed that the container is detachable from the main body of the image forming apparatus. For example, JP-B-4-23782, JP-B-4-38362, JP-A-63-78170, and JP-A-4-291.
Japanese Unexamined Patent Publication No. 66 discloses a rotary developing device in which a plurality of developing devices are integrally attached or detached or replaced. Further, for example, JP-A-60-208779 and JP-A-60-2
No. 14377, JP-A-61-73163, JP-A-61-103175 and the like disclose a rotary developing device in which a plurality of developing devices mounted on a support are separately attached and detached. There is.

By the way, a general general document is mainly black, and the amount of other colors used is smaller than that of black. Therefore,
Of the multiple developing devices, the black developing device is used much more frequently, and the degree of deterioration of the functional parts such as the developer and the developing roller or the toner consumption amount between the black developing device and the developing devices of other colors. Is different. In addition, a difference in the frequency of use appears to some extent between developing units of other colors.

For example, a plurality of developing devices of the same shape are arranged on the circumference of a rotating body, such as a rotary developing device described in Japanese Patent Publication No. 4-23782 and Japanese Patent Laid-Open No. 4-29166. In a developing device that is not provided with a toner replenishing or replenishing mechanism, it is necessary to replace the entire developing device when a toner end of one color occurs in a plurality of developing devices.
For this reason, there is a lot of waste by replacing the developing device even though the toners of other colors remain sufficiently or the developing device itself is still fully functioning, which causes a significant increase in running cost. Was there.

On the other hand, in the rotary developing device disclosed in Japanese Utility Model Publication No. 4-38362, the black developer storage amount, which is frequently used, is set larger than the developer storage amounts of other colors.
Compared to the above-mentioned device, waste is reduced and running cost rise is suppressed. However, there are variations in the usage status of the apparatus, and the entire developing apparatus is replaced when the toner is used up, so there are still many useless portions. In addition, from the viewpoint of protecting the global environment, this wasteful part is collected without developing the developing device made of various materials as it is,
This also leads to an increase in costs for the environment, system, equipment, etc. for dismantling and recycling, which causes substantial increases in equipment costs and running costs.

The developing device described in Japanese Patent Laid-Open No. 63-78170 is such that a plurality of developing devices of the same shape are integrally arranged on the circumference of the rotating body, and are consumed by the toner end of each color. To replenish the toner. In this developing device, the reliability of the developing device itself is sufficiently high, and if the life (reliability) of the main body of the image forming apparatus is commensurate, it suffices to supply toner only to the developing device. However, in reality, cleaning, inspection, adjustment, repair, and replacement of the developing device and each part, and in the device using the two-component developer, the developer (carrier) needs to be replaced regularly.

Further, in the developing device described in Japanese Patent Laid-Open No. 63-78170, a developing device is provided with a slider that is slidable in the main body of the image forming device while carrying the rotary developing device. The workability is improved because the maintenance work is performed and the developing device is replaced.
However, in order to carry a developing device equipped with a plurality of developing devices, the slider needs to have a complicated and strong structure, which is costly, and when the developing device is replaced, the entire device is also replaced. As in the case of the above-mentioned known example, there is much waste, which causes a large increase in running cost.

For developing devices in which a plurality of developing devices are integrally attached and detached, Japanese Patent Laid-Open Nos. 60-208779, 60-214377, and 61-73163 are available.
The rotary type developing device described in Japanese Patent Laid-Open No. 61-103175 and Japanese Patent Laid-Open No. 61-103175 is such that a plurality of developing devices mounted on a support are separately attached and detached. These developing devices are attached / detached at a predetermined developing device attachment / detachment or exchange position and are exchanged as necessary, as described in, for example, JP-A-60-208779 and JP-A-61-103175. Therefore, at the time of maintenance work (maintenance) or replacement, only the developing device that needs maintenance work or replacement can be attached to and detached from the image forming apparatus.

However, in these developing devices, although each developing device is handled individually, the mounting and demounting operation of the developing device is complicated, and each developing device or a developer carrying member provided in each developing device ( It is difficult to position the developing roller) at a predetermined position, and in some cases, fine adjustment is required to fix each developing device. For example, JP-A-60-21
A method is known in which positioning rollers that maintain the positional relationship with the latent image carrier are provided at both ends of the developer carrier, as in the developing device described in Japanese Patent No. 4377, but foreign matter and developer adhere to the rollers and The positional relationship may change, resulting in image defects.

Further, the above-mentioned JP-A-60-208779, JP-A-60-214377, and JP-A-61-7.
In the rotary developing devices described in Japanese Patent No. 3163 and Japanese Patent Laid-Open No. 61-103175, a plurality of developing devices mounted on a support are provided in the front direction of the main body of the image forming apparatus, that is, as the axis of the latent image carrier. The developing device is attached and detached in the parallel direction. However, for example, in these developing devices, the paper supply direction and the paper discharge direction to the device main body in which a necessary work space is secured outside the image forming apparatus and the developing device attachment / detachment direction are different, so It is necessary to have a wide working space for attaching and detaching the developing device at a position different from the working space for replenishment, and further, for maintenance of the inside of the device in the direction of paper replenishment to the main body of the device and the direction of paper ejection. If an opening / closing cover for this purpose is provided, a dedicated opening / closing door for taking out the developing device is required separately from the opening / closing cover, for example, on the side plate of the image forming apparatus main body. In addition, a mechanism and a device for preventing the occurrence of scratches on the surface of the latent image carrier when the developing device is attached and detached are required.

[0013]

Therefore, the applicant of the present invention is
In order to improve the workability such as maintenance and replacement of the developing device and the developing device, and to provide an image forming apparatus capable of reducing the running cost, only a specific developing device that is frequently used among a plurality of developing devices is used. , A device that can be attached to and detached from the developing device main body is proposed (Japanese Patent Application No. 6-2
39607). In particular, the same application (Japanese Patent Application No. 6-239)
No. 607), when the developing device is attached and detached in the direction perpendicular to the rotary shaft of the developing device in the direction of contacting and separating from the rotary shaft, Since the direction of paper replenishment and paper ejection to the main body and the direction of mounting and demounting the developing device can be the same, the work space for paper replenishment and the work for mounting and demounting the developing device can be done. Can be shared with space. Further, since an opening / closing cover for the maintenance such as replacement of the latent image carrier inside the apparatus is provided in the paper replenishing direction and the paper discharging direction, the side plate of the image forming apparatus main body different from the position of the opening / closing cover is provided. It is not necessary to provide a dedicated opening / closing door for taking out the developing device, and the developing device can be replaced by the same operation as the replacement of the latent image carrier, for example. Further, when the developing device is attached or detached, the surface of the latent image carrier is not scratched.

However, in the image forming apparatus constructed so that the developing device is attached / detached in a direction perpendicular to the rotating shaft of the developing device in a direction in which it separates from / contacts the rotating shaft, the image forming operation is not performed. When the developing device rotates accordingly, a centrifugal force acts in a linear direction of a line connecting the center of gravity of each developing device and the center of the rotating shaft of the developing device, and the developing device may be detached from the developing device main body and fall off. is there.

The present invention has been made in view of the above problems, and an object of the present invention is to prevent development of each developing device from dropping due to centrifugal force acting on each developing device when the developing device is rotated. An image forming apparatus including the apparatus is provided.

[0016]

In order to achieve the above object, the invention of claim 1 is such that a plurality of developing devices accommodating a powder developer are arranged around a rotary shaft, and the plurality of developing devices are arranged. Among the plurality of developing devices, at least one of the plurality of developing devices is rotated by rotating any one of the developing devices to a developing position facing the latent image carrier about the rotation shaft. In an image forming apparatus equipped with a developing device that can be attached to and detached from the main body of the image forming apparatus, the direction of attaching and detaching the developing device to the main body of the developing device is set in the plane perpendicular to the rotation axis of the developing device. It is characterized in that the direction is different from the straight line connecting the center of the moving axis and the center of gravity of the developing device.

According to a second aspect of the present invention, a plurality of developing devices containing powder developer are arranged around the rotation shaft, and any one of the plurality of developing devices is connected to the rotation shaft. For developing by rotating to a developing position facing the latent image carrier, and at least one developing device of the plurality of developing devices can be attached to and detached from the main body of the image forming apparatus. In an image forming apparatus equipped with the developing device, the direction of attachment and detachment of the developing device to and from the developing device main body is made rotatable about the rotation axis center and the developing device within a plane perpendicular to the rotation axis of the developing device. It is characterized in that the direction is different from the straight line connecting the rotation center of the provided developer carrier.

According to a third aspect of the present invention, in the image forming apparatus according to the second aspect, the direction in which the developing device is attached to or detached from the developing device main body is within a plane perpendicular to the rotating shaft of the developing device. It is characterized in that the direction is inclined by 45 ° or more with respect to the straight line connecting the center and the center of rotation of the developer carrier rotatably provided on the developing device.

Particularly, the invention of claim 4 is the same as claim 1 or 2.
In the image forming apparatus, the developing device includes a shaft body including a rotating shaft of the developing device, and a partition member extending from the shaft body so as to partition adjacent developing devices mounted in the developing device. A developing device support for detachably supporting the developing device is provided, and the developing device is moved along the surface of one of the two partitioning members facing the developing device so as to be attached and detached. It is a thing.

According to a fifth aspect of the present invention, in the image forming apparatus according to the fourth aspect, guide portions for guiding the developing device in the attachment / detachment direction are provided at both ends of the partition member in the rotation axis direction of the developing device. A stopper member for fixing the developing device in the detaching direction is provided.

In particular, the invention of claim 6 is the image forming apparatus of claim 5, wherein the stopper member is positioned and fixed while the developing device is pressed in the mounting direction. It is characterized by.

In particular, the invention of claim 7 is the image forming apparatus according to claim 4, wherein the developing device facing the mounted developing device 2
Among the two partition members, the surface of the partition member different from the partition member having the surface along the attachment / detachment direction of the developing device is used for the positioning at the time of mounting the developing device.

In particular, the invention of claim 8 is the image forming apparatus of claim 7, wherein the surface of the partition member for positioning the developing device and the developer rotatably provided on the developing device. The partition member is provided with an engaging portion for positioning the developing device along a line of intersection including a rotation axis of the carrier and a plane perpendicular to the surface of the partition member. It is characterized in that an engaged portion which engages with the engaging portion is provided.

[0024]

According to the invention of claim 1, the direction in which the developing device is attached to and detached from the main body of the developing device is a straight line connecting the center of the rotating shaft and the center of gravity of the developing device in a plane perpendicular to the rotating shaft of the developing device. Since the direction is different from that, when the developing device is rotated with the image forming operation, even if centrifugal force acts in the linear direction connecting the center of gravity of the developing device and the center of the rotation shaft of the developing device, It becomes difficult for the developing device to come off from the developing device.

Although it is difficult to actually confirm the center of gravity of the developing device, the developer carrying member of the developing device is usually composed of a metal roller portion and a shaft member and has a relatively large weight. A linear direction connecting the center of the rotation axis and the center of rotation of the developer carrier of the developing device in a plane perpendicular to the rotation axis is
It approaches the direction of the centrifugal force that acts on the center of gravity of the actual developing device.

Therefore, according to the second aspect of the invention, the mounting and dismounting direction of the developing device with respect to the main body of the developing device is made rotatable about the center of the rotating shaft and the developing device within a plane perpendicular to the rotating shaft of the developing device. By setting the direction different from the linear direction connecting the rotation center of the provided developer carrier, the center of gravity of the developing device and the rotation of the developing device when the developing device is rotated in accordance with the image forming operation. Even if a centrifugal force acts in the direction of the straight line connecting the center of the shaft, the developing device does not easily come off from the developing device.

Particularly, in the third aspect of the invention, the direction of attachment and detachment of the developing device with respect to the main body of the developing device is made rotatable with respect to the center of the rotating shaft and the developing device within a plane perpendicular to the rotating shaft of the developing device. By making the direction inclined by 45 ° or more with respect to the straight line connecting the rotation center of the provided developer carrier, the center of gravity of the developing device can be adjusted when the developing device is rotated with the image forming operation. Even if a centrifugal force is applied in a straight line connecting the center of the rotation axis of the developing device, the developing device is more reliably prevented from being separated from the developing device.

In particular, in the invention of claim 4, the developing device supporting member for detachably supporting the developing device is such that the developing device supporting member is adjacent to the shaft member including the rotating shaft of the developing device and the developing device mounted on the developing device. And a partition member extending from the shaft so as to partition. Then, by moving the developing device along the surface of one of the two partitioning members facing the developing device and attaching or detaching the developing device, the developing device can be easily and reliably mounted on a surface perpendicular to the rotation axis of the developing device. In a direction different from a straight line connecting the center of the rotating shaft and the center of gravity of the developing device, or in a plane perpendicular to the rotating shaft of the developing device so that the rotating shaft center and the developing device can freely rotate. The developing device can be attached and detached from a direction different from the straight line connecting the rotation center of the provided developer carrier.

In particular, in the fifth aspect of the invention, when the developing device is attached or detached, the developing device is guided in the attaching and detaching direction by the guide members provided at both ends of the partition member in the rotation axis direction of the developing device. . Further, the stopper members provided at both ends of the partition member fix the developing device in the detaching direction which is a direction different from the direction in which the centrifugal force acts.

In particular, according to the invention of claim 6, the developing device has a backlash with respect to the developing device support by positioning and fixing the developing device with the stopper member while being pressed in the mounting direction. Fixed without.

In particular, in the invention of claim 7, of the two partition members facing the developing device mounted on the developing device, a partition member different from the partition member having a surface along the mounting and demounting direction of the developing device is used. By positioning the developing device at the time of mounting by the surface, the developing device is accurately positioned.

Particularly, in the invention of claim 8, the surface of the partition member for positioning the developing device at the time of mounting the developing device and the developer carrying member rotatably provided on the developing device. The engaging portion of the partition member and the engaged portion of the developing device are engaged with each other to position the developing device along a line of intersection that includes the rotation axis of the partition member and that intersects the surface of the partition member at right angles. By
The position of the developer carrier, which requires the most positional accuracy during image formation, is accurately positioned.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a full color printer which is an image forming apparatus will be described below. First, the schematic configuration of the full-color printer according to this embodiment will be described with reference to FIG. After the photosensitive belt 1 as a latent image carrier is uniformly charged by the charging roller 2,
The laser optical device 3 scans and exposes on the basis of image information to form an electrostatic latent image on the surface. Here, the image information to be exposed is monochromatic image information in which a desired full-color image is decomposed into color information of yellow, magenta, cyan, and black.
The formed electrostatic latent image is developed with the predetermined yellow, magenta, cyan, and black toners by the rotary developing device 4 described later, and each color image is formed on the photosensitive belt 1.

Photosensitive belt 1 rotating in the direction of arrow A in the figure
The respective color images formed on the upper surface of the intermediate transfer belt 5 which rotates in the direction of arrow B in the figure in synchronization with the photoconductor belt 1 are sequentially transferred in layers of yellow, magenta, cyan and black. The yellow, magenta, cyan, and black images superposed on the intermediate transfer belt 5 are transferred by the transfer roller 6 onto the transfer paper 11 conveyed from the paper feed table 8 through the paper feed roller 9 and the registration roller 10 to the transfer section. It is transferred at once. After the transfer is completed, the transfer paper 11 is fixed by the fixing device 7 to complete a full-color image.

Next, the rotary developing device 4 used in the full-color printer of this embodiment will be described with reference to FIGS. FIG. 2 is a front view showing an internal configuration of the rotary developing device 4. A rotary developing device (also referred to as a revolver developing device or a rotary developing device; hereinafter simply referred to as “developing device”) 4 is arranged near the photoconductor belt 1. In the developing device 4, the developing device support 20 including the rotation center O and rotatably provided about the rotation center O is rotated in the direction of arrow C by a drive mechanism (not shown). Further, the developing device support 20 has a shape that divides the developing device 4 into four parts, and detachably supports the respective color developing devices 21Y, M, C, and K by the configuration described later. Note that FIG. 2 shows a state in which the developing device 21K is in the developing position.

Each developing device 21Y, M, C, K has a cylindrical developing roller 22Y, M, C, K as a developer bearing member.
Is provided. These developing rollers 22Y, M, C,
K is arranged so that a part thereof is exposed to the outside through an opening 23a provided in the casing 23, and rotates in the direction of arrow C in the drawing in synchronization with color information to develop a corresponding electrostatic latent image. . Each of the developing devices 21Y, M, C, and K is a developing device using a non-magnetic one-component developer, and stores yellow, magenta, cyan, and black toners, respectively, and selectively develops at a rotation center O as a center. When the electrostatic latent image formed on the photoconductor belt 1 is sequentially developed, and the developed images are superimposed on the intermediate transfer belt 5 and the transfer paper 11 as described above, a full-color image is formed. Form.

Next, the rotary developing device 4 used in the full-color printer of this embodiment will be described with reference to FIGS. FIG. 2 is a front view showing an internal configuration of the rotary developing device 4. A rotary developing device (also referred to as a revolver developing device or a rotary developing device; hereinafter simply referred to as “developing device”) 4 is arranged near the photoconductor belt 1. In the developing device 4, the developing device support 20 including the rotation center O and rotatably provided about the rotation center O is rotated in the direction of arrow C by a drive mechanism (not shown). Further, the developing device support 20 has a shape that divides the developing device 4 into four parts, and detachably supports the respective color developing devices 21Y, M, C, and K by the configuration described later. Note that FIG. 2 shows a state in which the developing device 21K is in the developing position. (Hereinafter, margin)

Each developing device 21Y, M, C, K has a cylindrical developing roller 22Y, M, C, K as a developer bearing member.
Is provided. These developing rollers 22Y, M, C,
K is arranged so that a part thereof is exposed to the outside through an opening 23a provided in the casing 23, and rotates in the direction of arrow C in the drawing in synchronization with color information to develop a corresponding electrostatic latent image. . Each of the developing devices 21Y, M, C, and K is a developing device using a non-magnetic one-component developer, and stores yellow, magenta, cyan, and black toners, respectively, and selectively develops at a rotation center O as a center. When the electrostatic latent image formed on the photoconductor belt 1 is sequentially developed, and the developed images are superimposed on the intermediate transfer belt 5 and the transfer paper 11 as described above, a full-color image is formed. Form.

FIG. 3A is a front view showing the black developing device 21K together with the photosensitive drum 1. Since the developing devices 21Y, M, C, K for each color have the same configuration and the same operation, only the black developing device 21K will be described below.
In FIG. 3A, the developing device 21K is arranged below the photoconductor belt 1 and serves as a non-magnetic one-component developer for the electrostatic latent image formed on the photoconductor drum 1 located above the developing device 21K. Supply toner. In the opening 23a formed above the developing device 21K at the developing position, the developing roller 22K faces the photoconductor drum 1 so as to face the photoconductor drum 1 and has a predetermined peripheral speed ratio with the photoconductor drum moving direction. It is arranged to rotate in the direction. Further, below the developing roller 22K, a supplying roller 24K as a toner supplying member made of an elastic material such as polyurethane foam is provided.
It is provided so as to rub against the developing roller 22K and to rotate in the same direction with respect to the developing roller 22K at a predetermined peripheral speed ratio. On the downstream side of the supply roller 24K in the moving direction of the developing roller 22K, a blade 25K made of an elastic material such as urethane rubber is provided in the vicinity of the opening 23a.
However, the vicinity of one end thereof is provided so as to contact the developing roller 22K.

Further, as shown in the side sectional view of the developing device 21K of FIG. 3B and the perspective view of FIG. 4, a toner accommodating portion 40K is provided on the front side of the developing device 22K. First
First toner transport screw 2 as a developer transport means of
6K is arranged in parallel with the developing roller 22K and the supply roller 24K from the toner storage portion 40K to the other side plate of the developing device 4, and is arranged from the right side to the left side in FIG. 3B (from the front side to the rear side in FIG. 3A). 2) and the supply roller 24K so as to convey the toner toward the direction (4), and the toner is rotated at a predetermined peripheral speed ratio. The casing 23K is arranged so that a part thereof contacts the supply roller 24K, and the developing roller 22K, the supply roller 24K, and the casing 23K.
As a result, a toner carrying space 27K surrounding the toner carrying member 26K is formed.

Then, the first toner carrying screw 26K
By rotating in a predetermined direction, the toner storage unit 4
The toner is conveyed from 0K into the toner conveying space 27K, and the toner is supplied onto the supply roller 24K. The toner supplied onto the supply roller 24K is
Is supplied while being charged on the surface of the developing roller 22K, and is carried on the surface of the developing roller 22K. Developing roller 2
The toner carried on the 2K surface is made into a thin toner layer having a uniform thickness and a predetermined thickness by the blade 25K.
The electrostatic latent image formed on the surface of is developed by contact or non-contact development.

The static elimination brush 28K made of conductive fibers or the like in FIG. 3A is in contact with the developing roller 22K over the entire width in the axial direction, and a predetermined voltage difference is provided between the developing roller 22K and the developing roller 22K. History of difference in toner consumption on the developing roller 22K with respect to the electrostatic latent image on the photosensitive drum 1,
In addition, the occurrence of an afterimage due to this is prevented.

By the way, the toner not used in the developing step is conveyed by the first toner conveying screw 26K to the end portion of the developing device opposite to the toner containing portion 40K. A toner circulating unit 29K is provided outside the effective diameter portion in the axial direction of the developing roller 22K and the supply roller 24K. First
The toner carried by the toner carrying screw 26K to the toner circulating portion 29K falls to the lower part of the developing device 21K due to gravity.

Below the developing device 21K, a second toner carrying screw 30K as a second developer carrying member is arranged in parallel with the developing roller 22K, the supply roller 24K and the first toner carrying screw 26K. The toner is rotated so as to convey the toner in the direction opposite to the direction of the toner conveying screw 26K, and the toner not used in the developing process is conveyed to the toner containing portion 40K. First toner transport screw 2
By appropriately setting the carry amounts of 6K and the second toner carrying screw 30K, it is possible to detect the toner amount in the developing device 21K and to perform the complicated feed amount control without supplying the feed roller 24.
Therefore, it is possible to provide a small-sized developing device which can be supplied on the surface of K, has a large degree of freedom in layout, and has a small cross-sectional occupation ratio with respect to the photoconductor.

Incidentally, the toner cartridge 41K in FIG.
Is removably mounted in the toner storage portion 40K, and is mounted or replaced when the developing device 4 is newly mounted or at the toner end, and a required amount of toner is always stored in the toner storage portion 40K.

Next, the structure for attaching and detaching the developing device 21 and its attaching and detaching operation will be described. At times other than the image forming operation, that is, before and after the image forming operation, the developing device 4 stands by and stops at the home position as shown in FIGS. 5A and 5B. In this embodiment, the developing roller 22K of the black developing device 21K and the developing roller 2 of the cyan developing device 21C.
The home position is a position at which the rollers 22K and 22C do not contact the photoconductor 1 at an approximately midpoint of 2C. At this position, the black developing device 21K, which is the most frequently used, is
This is the position where the developing position can be reached earlier and more accurately by the rotation of the developing device 4 in the direction of the arrow C in the drawing during image formation. In addition, the photosensitive drum 1 and the developing roller 22 are prevented from being deteriorated or scratched due to unnecessary contact between the photosensitive drum 1 and the developing roller 22 during non-operation, and the toner is prevented from adhering or sticking to the outside of a predetermined area. It is also a position.

As described above, most of the normal output images are black and white images, and it is said that the ratio with a color image is 8: 2 or 9: 1. Therefore, the black developing device 21K
Is forced to operate many times as much as the other color developing devices 21Y, M, and C. When a few thousand images are output, the toner in the toner cartridge 41K becomes empty, and the toner end sensor known in the art such as an optical sensor or a magnetic sensor (not shown) detects the toner end.
Normally, when the toner end is reached, as shown in FIG. 6, only the toner cartridge 41K is attached / detached in the direction of arrow D and replaced. Although the black toner cartridge 41K is attached and detached and replaced in FIG. 6, the same applies to other colors.

If the reliability of the developing device 21 is sufficiently high and it is commensurate with the reliability of the printer main body, and if there is no special abnormality, only the above-mentioned toner cartridge 41 will be replaced. Depending on the usage status of 2
Maintenance work (maintenance) and replacement of No. 1 are required. In particular, as described above, since the black developing device 21K is used frequently, maintenance and replacement work is required more frequently than developing devices of other colors. In addition, the developing devices 21Y, M, and C of other colors have slightly different usage conditions, so that maintenance and replacement intervals are different. In this way, even if one of the developing devices needs to be maintained or replaced, the developing devices of other colors are almost normal. Therefore, workability is poor in a structure in which, when maintenance or replacement of only a specific developing device is required, another developing device must be attached / detached or replaced at the same time. Further, even a developing device that can be fully used will be replaced, resulting in a lot of waste, resulting in a large developing device cost, replacement cost, and running cost. Further, from the viewpoint of protection of the global environment and recycling, the replaced developing device is generally recovered, and there are problems in recoverability, decomposability, and recyclability.

Therefore, in the present embodiment, of the plurality of developing devices having different frequencies of use, for example, only the developing device that needs maintenance and replacement can be attached to and detached from the developing device 4 and the printer main body. This makes it possible to easily perform operations such as maintenance and replacement, and further reduce costs and improve recyclability. For example, the black developing device 21
When maintenance or replacement is required for K, in this embodiment, as shown in FIG. 7, the upper cover 51 of the printer body 50 is opened and the photoconductor unit 52 is removed upward. next,
As shown in FIG. 8, only the black developing device 21K is detached from the developing device 4 and the printer 50 in the direction of arrow D and removed. As shown in FIG. 9, it is also possible to work with the toner cartridge 41K removed in advance. Since only the black developing device is attached and detached and replaced, workability is high and waste during replacement can be reduced.

Next, referring to FIGS. 10 to 12, an example of the structure of the attachment / detachment and positioning mechanism of the black developing device 21K will be described. FIG. 10A shows four color developing devices 21Y, M, C, K.
FIG. 3 is a perspective view of a developing device support 20 that detachably supports the developing device. The developing device support 20 includes a shaft 201 that includes the rotation axis O of the developing device 4 as a center and a shaft body 20 that partitions the developing devices 21Y, M, C, and K mounted on the developing device 4 from each other.
It has four partition members 202Y, M, C and K extending from 1. The developing device 4 is divided into four equal parts by the partition member 202, and the developing devices 21Y,
M, C and K are detachably supported. In addition, the developing device 4
At both ends of the partition member 202 in the direction of the rotation axis of the projecting member, a convex guide portion 202a that guides the developing device 21 in the attaching / detaching direction is provided.
Are formed.

As shown in the left and right side views of the developing device 21 in FIGS. 10 (a) and 10 (b), both longitudinal side plates 31, 31
The partition member 2 of the above-mentioned developing device support 20 is provided below 32.
02, the convex portions 31a and 32a corresponding to the convex guide portion 202a and the grooves 31b and 32b are formed. For example, when the black developing device 21K is attached to the printer main body 50 and the developing device support 20, one of the two partition members 202 facing the developing device 21K.
The guide portion 202a provided on the K and the developing device side plate 31
The convex portions 31a and 32a and the grooves 31b and 32b formed under the K and 32K are engaged with each other, and the developing device 21K is pushed in along one surface 202b of the partition member 202K. As a result, the developing device 21K can be easily and reliably guided to the predetermined mounting position.

Of the two partition members 202 facing the developing device 21, the surface 2 along the attaching / detaching direction of the developing device 21.
A partition member 2 different from the partition member 202 faced by 02b
02 surface 202c, for example, the developing device 21 has a black developing device 2
In the case of 1K, pin-shaped projections 202d which are positioning engaging portions are formed at both ends of the surface 202b of the partition member 202Y facing the developing device 21K. In contrast,
As shown in FIG. 10C, the developing device side plate 3 of the developing device 21.
On the back surface of 1, 32, circular and elongated hole boss portions 31c,
32c is provided. When the developing device 21 is mounted, the protrusion 202d and the boss portions 31c and 32c are engaged with each other,
1 is positioned in the direction perpendicular to the mounting direction, and one surface 202c of the partition member 202 and the developing device 2
Positioning of the developing device 21 in the mounting direction is performed by the butting of the back surface of the developing device 21.

As shown in FIG. 11 (a), the surface 202c of the partition member 202 for abutting the developing device and the surface 202 of the partition member including the rotating shaft of the developing roller 22.
along the line of intersection with the plane perpendicular to c.
By arranging 02d and the bosses 31a and 32a in an aligned manner, the position of the developing roller 22, which requires the most positional accuracy during image formation, can be easily determined and managed with high accuracy.

When the developing device 4 rotates in accordance with the image forming operation, each developing device 21 has a line direction (arrow E in FIG. 11B) connecting the cross-sectional center of gravity of the developing device 21 and the rotation axis O.
Direction), centrifugal force acts on the developing device 21 and the developing device 21 moves to the developing device support 2
Trying to break away from zero. Normally, the linear direction connecting the developing roller 23, which is attached to the outermost peripheral portion of the rotary developing device 4 and has a metal roller portion or shaft portion, to the center of the rotation axis O is the centrifugal force direction acting on the center of gravity. It's getting closer.

Therefore, in this embodiment, as shown in FIG. 11B, the developing device attaching / detaching direction (the direction of arrow D in FIG. 11B), the center of the rotation axis O, and the center of gravity of the cross section of the developing device 21 are defined. The angle θ with the connecting straight line direction (the direction substantially the same as the E direction in which the centrifugal force acts) is about 60 °. As described above, the developing device support 20 and the developing device 21 include the guide portion 202a provided on the partition member 202 of the developing device support 20, the convex portions 31a, 32a provided on the developing device side plates 31, 32, and Groove 3
Since it can move only in the direction along one surface 202b of the partition member 202 by engaging with 1b and 32b, it is possible to prevent the developing device 21 from coming off and coming off due to the influence of centrifugal force.
When the developing device 21 is attached and detached in the radial direction from the rotation axis O of the developing device 4, the attaching and detaching direction of the developing device 21 and the developing device 21
The angle θ between the center of gravity of the cross section and the straight line connecting the center of the rotation axis O of the developing device 4 is preferably large. In practice, the attaching / detaching direction of the developing device 21, the rotation axis of the developing roller 23, and the developing The angle between the linear direction connecting the rotation axis O of the device 4 and
It is desirable that the angle be 5 ° or more.

Further, as shown in FIG. 12A, the guide portions 20 at both ends of the partition member 202 of the developing device supporting member 20.
A stopper member 203 is arranged in the vicinity of 2a in a state of being pressed by a leaf spring 204 in the direction of arrow F in the figure. An arrow G in FIG. 12B indicates that the guide portion 202a and the convex portion 32a provided on the developing device side plate 32 are engaged with each other.
When pushed in the direction, the tapered portion 32d of the convex portion 32a
This causes the stopper member 203 to move in the direction of arrow H toward the spring 20.
It moves against the pressing force of 4. When the developing device 21 is further pushed in, the locking portion 32e formed in a part of the convex portion 32a eventually engages with the tip 203a of the stopper member 203. At this time, as described above, the one surface 202c of the partition member 202 and the rear surface of the developing device 21 are butted to position the developing device 21 in the mounting direction.

Then, as shown in FIG. 12C, the positions of the engaging portion 32e and the tip 203a of the stopper member 203 are slightly displaced so that the pressing force of the spring 204 causes the developing device 21 to move in the direction of arrow I in the figure. Will be positioned while being pressed. As a result, the developing device 21 can be easily and accurately fixed to the developing device support 20 without any play. Further, as described above, since the force of the centrifugal force in the separating direction of the developing device 21 is sufficiently weak, it is not necessary to take a large pressing force of the spring 204, and the developing device 21 is not required.
When the developing device 21 is detached from the developing device support 20, the developing device 21 can be easily removed by pulling the developing device 21 with a force that slightly resists the pressing force of the spring 204.

The partition member 20 of the developing device support member 20
Also in the vicinity of the guide portion 202a at the other end of FIG.
A stopper member 203 is provided in the same manner as 2, and a tapered portion 32d and a locking portion 32e are also formed on the convex portion 31a of the other developing device side plate 31 as in FIG.

In the above embodiment, a full-color printer using four colors of yellow, magenta, cyan and black has been described, but so-called multi-color image formation using black, red, blue and other colors. It can also be applied to devices.

[0060]

According to the invention of claim 1 or 2, the direction of attachment and detachment of the developing device with respect to the developing device main body is such that the center of the rotating shaft and the center of gravity of the developing device are within a plane perpendicular to the rotating shaft of the developing device. By making the direction different from the linear direction connecting the and, when the developing device is rotated in accordance with the image forming operation, the centrifugal force is applied in the linear direction connecting the center of gravity of the developing device and the rotation axis center of the developing device. Even if it works, it is difficult for the developing device to come off from the developing device, so that the developing device can be prevented from coming off.

Further, since the developing device is attached and detached in the direction perpendicular to the rotary shaft of the developing device in the direction of contacting and separating from the rotary shaft, Since the transfer paper discharge direction and the developing device mounting / removing direction can be the same direction, the working space for paper supply and the working space for mounting / demounting the developing device should be shared. Therefore, there is an effect that it is not necessary to take a large space around the image forming apparatus. Further, in the case where an opening / closing cover for the maintenance such as replacement of the latent image carrier inside the apparatus is provided in the paper replenishing direction or the paper discharging direction, the image forming apparatus main body different from the position of the opening / closing cover is provided. There is no need to provide a dedicated opening / closing door for taking out the developing device on the side plate, and there is an effect that the developing device can be replaced by the same operation as the replacement of the latent image carrier, for example. Further, there is an effect that a scratch or the like is not generated on the surface of the latent image carrier when the developing device is attached or detached.

In particular, according to the second aspect of the invention, the direction in which the developing device is attached to and detached from the main body of the developing device is set so that the center of the rotating shaft and the metal roller portion or shaft member are within a plane perpendicular to the rotating shaft of the developing device. The direction of the center of gravity of the developing device, which is difficult to confirm in practice, is not known because the direction is different from the straight line that connects the rotation center of the developer carrier that has a relatively large weight and is relatively easy to confirm. There is an effect that the attaching / detaching direction of the developing device can be set.

Further, according to the third aspect of the invention, the attaching / detaching direction of the developing device with respect to the main body of the developing device is rotated between the center of the rotating shaft and the developing device within a plane perpendicular to the rotating shaft of the developing device. By making the direction inclined by 45 ° or more with respect to the linear direction connecting the rotation center of the developer carrier that is freely provided, when the developing device is rotated with the image forming operation, Even if a centrifugal force acts in the direction of the straight line connecting the center of gravity and the center of the rotation axis of the developing device, the developing device is more reliably separated from the developing device and is prevented from falling off.

Further, in particular, according to the invention of claim 4, by moving the developing device along the surface of one partitioning member of the two partitioning members facing the developing device and attaching / detaching it, it is possible to easily and surely. , In a plane perpendicular to the rotation axis of the developing device from a direction different from the straight line connecting the center of the rotation axis and the center of gravity of the developing device, or in the plane perpendicular to the rotation axis of the developing device. It is said that the developing device can be guided and mounted to a predetermined mounting position from a direction different from a straight line connecting the center of the moving shaft and the rotation center of the developer carrier rotatably provided on the developing device. effective.

Further, according to the fifth aspect of the invention, when the developing device is attached or detached, the developing device is guided in the attaching and detaching direction by the guide members provided at both ends of the partition member in the rotation axis direction of the developing device. By doing so, the developing device can be guided to a predetermined mounting position and mounted, and the stopper members provided at both ends of the partition member fix the developing device in the detaching direction, so that the developing device is further prevented from falling off. The effect is that you can do it. Furthermore, since the mounting and demounting direction of the developing device can be made one direction of the guide direction of the guide member, there is an effect that the influence of centrifugal force can be further reduced. Further, since the stopper member fixes the developing device in a direction different from the direction in which the centrifugal force acts, there is an effect that the developing device can be reliably fixed with an extremely small force.

In particular, according to the invention of claim 6, the developing device is positioned and fixed by the stopper member while being pressed in the mounting direction, so that the developing device has a backlash against the support. Because it can be fixed without
There is an effect that it is possible to easily and accurately position the developing device in the attachment / detachment direction.

Further, according to the invention of claim 7, among the two partition members facing the developing device mounted in the developing device, a partition member different from the partition member having a surface along the mounting and demounting direction of the developing device. By positioning the developing device when it is mounted by the surface of the member, it is possible to position the developing device with higher accuracy.

In particular, according to the invention of claim 8, when the developing device is mounted, the surface of the partition member for positioning the developing device and the developer rotatably provided on the developing device. Positioning of the developing device by engaging the engaging portion of the partition member and the engaged portion of the developing device along the line of intersection including the rotation axis of the carrier and the plane perpendicular to the surface of the partition member. By performing the above, there is an effect that the position of the developer carrying member, which is required to have the highest positional accuracy at the time of image formation, can be accurately positioned.

[Brief description of drawings]

FIG. 1 is a front view showing a schematic configuration of a full-color printer according to an embodiment.

FIG. 2 is a schematic sectional view of a rotary developing device in the printer.

FIG. 3A is a schematic sectional view of a developing device in the developing device. (B) is a longitudinal sectional view of the developing device.

FIG. 4 is a schematic perspective view of the developing device.

5A and 5B are explanatory views of a home position of the developing device.

FIG. 6 is an explanatory diagram relating to attachment and detachment of a toner cartridge in the developing device.

FIG. 7 is an explanatory diagram relating to attachment / detachment of a photoconductor unit in the printer.

FIG. 8 is an explanatory diagram regarding attachment / detachment of a black developing device and a toner cartridge in the printer.

FIG. 9 is an explanatory diagram regarding attachment / detachment of a black developing device in the printer.

FIG. 10A is a perspective view of a developing device support of the developing device. FIG. 6B is a right side view of the developing device mounted in the developing device.
(C) is a left side view of the developing device.

FIG. 11A is an explanatory diagram of a mounting and demounting direction of the black developing device.
(B) is explanatory drawing of the attachment / detachment direction of the black developing device and the direction in which a centrifugal force acts.

12A to 12C are explanatory views of a fixing mechanism of the developing device.

[Explanation of symbols]

 4 developing device 20 developing device support 21 developing device 22 developing roller 31, 32 developing device side plate 31a, 32a convex part 31b, 32b groove 31c, 32c boss part 31d, 32d taper part 31e, 32e locking part 40 toner accommodating part 41 toner cartridge 50 printer main body 51 printer upper cover 201 shaft body 202 partition member 202a guide portion 202b surface of the partition member along the developing device attaching / detaching direction 202c surface of the partition member that faces the developing device 202d protrusion 203 stopper member 204 spring

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Yuichi Ueno 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Ucuke Fujishiro 1-3-6 Nakamagome, Ota-ku, Tokyo In Ricoh Co., Ltd. (72) Inventor Chiyako Kobayashi 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd.

Claims (8)

[Claims] 1. A plurality of developing devices, each containing a powder developer, are arranged around a rotation shaft, and any one of the plurality of developing devices is arranged around the rotation shaft as a latent image carrier. For developing by rotating to a developing position opposed to the developing device, wherein at least one developing device of the plurality of developing devices is detachably attached to the developing device main body and is replaceable In the apparatus, the direction in which the developing device is attached to and detached from the main body of the developing device is different from the linear direction connecting the center of the rotating shaft and the center of gravity of the developing device in a plane perpendicular to the rotating shaft of the developing device. An image forming apparatus characterized by the above. 2. A plurality of developing devices accommodating a powder developer are arranged around a rotating shaft, and any developing device of the plurality of developing devices is arranged around the rotating shaft as a latent image carrier. For developing by rotating to a developing position opposed to the developing device, wherein at least one developing device of the plurality of developing devices is detachably attached to the developing device main body and is replaceable In the apparatus, the direction of attachment / detachment of the developing device to / from the developing device main body is the center of the rotating shaft within a plane perpendicular to the rotating shaft of the developing device, and the developer carrying member rotatably provided on the developing device. An image forming apparatus characterized in that the direction is different from a straight line connecting the center of rotation. 3. A developer carrying member rotatably mounted on the developing device with respect to the direction of attachment and detachment of the developing device to and from the developing device main body in a plane perpendicular to the rotating shaft of the developing device. The image forming apparatus according to claim 2, wherein the image forming apparatus is tilted by 45 ° or more with respect to a straight line connecting the center of rotation of the body. 4. A developing device comprising: a shaft body including a rotating shaft of the developing device; and a partitioning member extending from the shaft body so as to partition adjacent developing devices mounted in the developing device. A developing device support for detachably supporting the developing device is provided, and the developing device is moved and removed along the surface of one of the two partitioning members facing the developing device. The image forming apparatus according to item 1 or 2. 5. A guide portion for guiding the developing device in the attaching / detaching direction and a stopper member for fixing the developing device in the detaching direction are provided at both ends of the partition member in the rotation axis direction of the developing device. The image forming apparatus according to claim 4, wherein the image forming apparatus is provided. 6. The image forming apparatus according to claim 5, wherein the stopper member is configured to be positioned and fixed in a state where the developing device is pressed in the mounting direction. 7. The mounting of the developing device by the surface of the partitioning member different from the partitioning member having a surface along the mounting / removing direction of the developing device, of the two partitioning members facing the mounted developing device. The image forming apparatus according to claim 4, wherein the positioning is performed. 8. A surface of a partition member for positioning the developing device when mounted, and a rotary shaft of a developer carrier rotatably provided on the developing device, and perpendicular to the surface of the partition member. The partition member is provided with an engaging portion for positioning the developing device, and the developing device is provided with an engaged portion that engages with the engaging portion along a line of intersection with a surface intersecting with The image forming apparatus according to claim 7, which is characterized in that.