JPH0646332B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus having a plurality of developing devices, each developing device having a different color developer. The present invention relates to a forming device.
In addition, the present invention is a two-color or three-color or more monochromatic color image,
Alternatively, the present invention can be suitably applied to an image forming apparatus such as a copying apparatus that obtains a full-color image, but is not limited to this, and various other copying apparatuses or color printing that constitutes an output unit of a computer, facsimile, or the like. It is also applicable to printers and the like.

(Prior Art) As is well known, in a developing device using a developer, particularly a two-component developer having a toner and a carrier, the developer is continuously used for a certain period, and The developer deteriorates (especially the carrier deteriorates), and therefore, it is necessary to regularly replace the developer in the developing device. Conventionally, as a means for facilitating the replacement of the developer, for example, Japanese Patent Publication No.
As disclosed in Japanese Laid-Open Patent Publication No. 8263, in a fixed developing device, a part of the circulation path of the developer is released and the deteriorated inside of the developing device is transferred to the outside of the developing device by a conveying means such as a screw. A method of transporting and collecting has been proposed.

However, in the above method, since the developing device collects the developer in the developing device facing the image bearing member which is the developing target, when the screen of the developing device and the developing roll are driven, the image bearing member stops. For this reason, the developer spills from the gap between the roll and the image carrier to contaminate the inside of the machine, or the developer is in sliding contact only at a specific position of the image carrier, which adversely affects the image carrier. It has the drawback of affecting.

On the other hand, when the developer is collected while moving the image carrier by the above method, the above-mentioned drawbacks can be avoided,
Since the developer adheres to the moving image carrier, electrical control such as bias voltage application must be performed to prevent this, and therefore the operation sequence of the machine becomes complicated and the developer collection operation is performed. There is a problem with time safety.

Further, if only the screen is rotated without rotating the developing roll, there is a drawback that the developer adhering to the developing roll cannot be collected.

(Object of the Invention) An object of the present invention is to provide an image forming apparatus capable of easily recovering a developer from a developing device.

Another object of the present invention is to provide an image forming apparatus in which the developer is collected at a position different from the developing position so that the image carrier is not damaged.

(Outline of the Invention) An image forming apparatus of the present invention includes an image carrier, and a latent image forming unit that forms an electrostatic latent image on the image carrier according to image information.
A developing container for accommodating the developer, a rotatable stirring member for stirring and moving the developer in the developing container, and a rotatable developer carrying member for carrying and carrying the developer in the developing container and applying it to the image carrier. A plurality of developing devices, each of which includes a plurality of developing devices for applying a different color developer to the image carrier at a developing position common to each developing device; and each of the plurality of developing devices. Common to the developing position and the developing devices,
Further, a developing device moving means for moving along a predetermined path including a developer collecting position different from the developing position, and the stirring of the developing device positioned at the developer collecting position to collect the internal developer. A driving unit that rotationally drives the member and the developer carrying and conveying member, and a developer carrying and conveying member that is rotationally driven by the driving unit, of the developing device positioned at the developer collecting position, facing each other through a gap; Magnetic attraction means for attracting and removing the developer on the developer carrying and conveying member by magnetic force, and when recovering the developer in a desired developing device, the desired developing device is moved to the developer collecting position. The desired stirring means of the developing device and the developer carrying and conveying member are rotated by the driving means, and the magnetic attraction means collects the developer in the developing container through the developer carrying and carrying member. Characterized by An image forming apparatus.

(Example) Hereinafter, the Example of this invention is described using drawing. Although the present embodiment shows a case where the present invention is applied to a full-color copying apparatus which is an example of an image forming apparatus, the present invention is also applied to an image forming apparatus such as a multi-color copying apparatus and a color recording apparatus having a computer output section. Of course it is possible.

1 to 8 show an apparatus described in Japanese Patent Application No. 60-38695 (Japanese Patent Application Laid-Open No. 61-200558) previously filed, the present invention is a further improvement thereof, The embodiment of the present invention is the same as that of Japanese Patent Application No. 60-38695, except for its improvement. Therefore, FIGS. 1 to 8 will be described before explaining the essential points of the present invention. In the figure, a latent electrostatic image bearing member, that is, a photosensitive drum 1 which is a developing object rotates in a direction of an arrow a, and a charging device 2, an exposure optical system 3, a developing device 4, a transfer system 5, and a cleaning device are arranged around the photosensitive drum 1. 6 are provided. The optical system 3 has a document scanning unit 3a and a color separation filter 3b. The developing device 4 includes, for example, a yellow developing device 4Y containing yellow toner and a magenta developing device 4 containing magenta toner.
M, a cyan developing unit 4C that stores cyan toner, and a black developing unit 4BK that stores black toner. In this embodiment, the developing device 4 has a central shaft 1
There is a rotating body 100 that rotates around 01. The developing body 4Y, 4 is detachably attached to the rotating body 100 at an angular interval of about 90 ° and in a vertical direction as shown in FIG.
M, 4C and 4BK are supported. Therefore, when the developing operation is performed, the rotating body 10 is driven by the drive motor M1.
When 0 rotates about the central axis 101 in the direction of the arrow b, a desired developing device of the developing devices 4Y, 4M, 4C, and 4BK is moved to the developing position A facing the photosensitive drum 1. FIG. 1 shows a state in which the developing device 4Y is at the developing position A.

Here, the rotational drive of the rotating body 100 will be further described with reference to FIG. The rotating body 100 has a ring gear 10 on the rear side.
2 is provided and is rotationally driven by a drive unit including a drive motor M1 provided in the main body apparatus and a gear train 200 that engages with the ring gear 102. On the other hand, the positioning of the rotating body 100 is performed by the positioning means 300 including the crank arm 302 rotatably provided on the pivot 301. The spring 303 pulls one end of the crank arm 302 so as to urge the pin 304 at the other end of the crank arm 302 in a direction in which the pin 304 is pressed against the positioning ring 103 provided on the rotating body 100. Moreover, the positioning ring 103 has a slot 104 arranged at a predetermined position around the positioning ring 103. When the rotating body 100 is rotated and one of the slots 104 is moved so as to be aligned with the positioning pin 304, the spring 303 rotates the crank arm 302 and presses the pin 304 into the slot 104 to rotate the rotating body 100. To prevent further rotation. In addition, the solenoid 305 connected to the crank arm 302 is operated,
The crank arm 302 is driven by the action of the spring 303.
By pulling and removing the pin 304 from the slot 104, the rotating body 100 can be freely rotated and rotated.

By the means as described above, the rotating body 100 can be rotated and stopped to rotate the desired developing device among the developing devices 4Y, 4M, 4C and 4BK to the developing position.

In FIG. 9, 105Y, 105M, 105C,
105BK is a developing device 4Y, 4M, 4C, 4BK, respectively.
Is a developing device support portion of the rotating body 100 that detachably supports and accommodates. The illustrated example shows a state in which all the developing devices are separated from the rotating body 100.

Further, in the present embodiment, the case where the rotating body 100 rotates to move the respective developing devices circularly is shown. However, the developing device of the present invention is
Not limited to this, for example, each developing device may be mounted on an endless moving body and each developing device may be moved along a non-circular orbit.

On the other hand, the transfer system 5 includes a transfer drum 5b having a gripper 5a.
And a transfer charger 5c provided inside the transfer drum 5b.

Therefore, in order to form a full-color image, first, the charger 2
By means of the exposure optical system 3, the photosensitive drum 1 uniformly charged in advance is subjected to color separation exposure in accordance with the color components of the original image to form a latent image on the photosensitive drum 1. This latent image is developed by the developing device at the developing position A where the developing device having the toner corresponding to the color component is moved in advance. Then, the developed image is transferred by the transfer charger 5c onto the transfer material previously supported on the transfer drum 5b. By repeating the above-mentioned steps a plurality of times according to the color components, the toners of respective colors are sequentially transferred onto the transfer material. Then, after the transfer process is finally ended, the transfer material is separated from the transfer drum 5b by the separating means 8, and the toner image is fixed on the transfer material by the fixing device 9 and discharged onto the tray 10. In this way, a full-color image corresponding to the original image is formed. In FIG. 1, 6 is a cleaner for collecting the toner remaining on the photosensitive drum 1, and 7 is a cleaner.
Is a cassette for accommodating the transfer material, and 11 is a conveying means for conveying the transfer material.

Further, in FIG. 1, the scraper 1 which can be brought into contact with and separated from the developing roller 46 of each developing device is provided below the developing device 4M.
2 and a container 13 for collecting the developer are provided. At the time of normal image formation, the scraper 12 has the developing roller 46.
Is located away from the rotation track region of the developing device 4. Then, when the developer is collected from the predetermined developing device, the scraper 12 is brought into contact with the developing roller 46. Further, the container 13 is detachable from the main body of the image forming apparatus so that the collected developer can be taken out of the apparatus and discarded. The details of the developer collecting operation will be described later.

Here, the developing devices 4Y, 4M, 4C, 4 in this embodiment
The structure of BK will be briefly described. Each developing device 4Y, 4
Since M, 4C and 4BK have the same structure, development position A
The developing device 4Y in FIG. 2 will be described with reference to FIG. FIG. 2 shows a state where the developing device 4Y is taken out from the rotating body 100. The developing device 4Y includes a developing container 41, and the inside of the developing container 41 is divided into two chambers by a partition plate 42, and rotatable transporting screws 43 and 44 are arranged in the respective chambers. The developer D is reciprocally circulated in the developing container 41 in the longitudinal direction of the developing container by the screws 43 and 44. In this example, the developer D is a magnetic two-component developer composed of toner and carrier. On the other hand, the developing roller 46 in this embodiment is a fixed magnet roller 46a as shown in the figure, and a developing sleeve for rotatably mounting around the magnet roller 46a in the direction of the arrow in the figure and carrying and carrying the developer. 46b.

In this embodiment, the magnet roller 46a is fixed and the developing sleeve 46b rotates. However, the present invention is not limited to this, and the magnet roller 46a and the developing sleeve 46b are relatively rotated. Good. Further, the developing roller 46 may itself be a magnet roller having multiple poles. Further, in this embodiment, since the developing device is provided with a developing roller having a magnetic means such as a magnet roller, even if the rotating body 100 is rotated and the developing device is rotated and moved, the developing is performed by the action of the magnetic field by the magnetic means. It is possible to prevent the toner from scattering from the container.

The amount of the developer drawn up by the S ₁ pole due to the rotation of the developing sleeve 46b is regulated by the doctor blade 45 and is conveyed as N ₁ pole → S ₂ → N ₂ → s ₃ pole. The N ₁ pole is the main developing pole, and the developer that is erected here develops the electrostatic latent image on the photosensitive drum 1, and then the developer on the developing sleeve 46b by the repulsive magnetic field of the S ₃ pole and the S ₁ pole. Drops in the developer container.

The rotating body, in which the developing device having the above-described configuration is mounted so that the developing roller thereof always faces the outside of the rotating body, causes the developing devices to sequentially rotate and move to the developing position, and the developing device moved to the developing position. Develops sequentially the latent images formed on the photosensitive drum by color separation exposure. However, as the number of times of image formation increases and the frequency of use of the developer in the developing device increases, the developer deteriorates. Especially, the carrier deteriorates. Therefore, it is necessary to collect the deteriorated developer and replace it with a new developer regularly. Therefore, in the present invention, when recovering the developer, the developing device having the developer to be recovered is moved to the developer recovery position.

Hereinafter, a method for collecting the developer will be described.

In this embodiment, the developer collecting position B is the position where the developing device 4M is located in FIG. 1, that is, the position where the developing device 4Y located at the developing position A is rotated by approximately 90 ° clockwise. . Now, it is assumed that a developer recovery command is issued by a means (not shown) and the developing device 4M is moved to the developer recovery position B so as to recover the developer. This is shown in FIG.

On the other hand, when the developer collection order is issued, the scraper 12
Is pressed against the developing roller 46 of the developing device 4M, and the driving force necessary for collecting the developer is transmitted only to the developing device 4M.
(The mechanism for contacting / separating the scraper 12 with the developing roller and the mechanism for transmitting the driving force to the developing device will be described later.
When the driving force is transmitted to M, the transporting screws 43 and 44 of the developing device 4M and the developing sleeve 46b of the developing roller 46.
Rotates. As a result, the developer is applied to the developing sleeve 46b.
The scraper 12 adheres to the upper side and is conveyed, but as the scraper 12 is in pressure contact with the developing sleeve 46b as shown in FIG.
It is forcibly stripped from 6b, reaches the outside of the restraint magnetic field by the magnet roller 46a provided in the developing sleeve 46b, and falls into the collecting container 13 arranged below the developing device 4M by the action of gravity. In addition, the transport screen 43
The developer around the carrier screen is stirred and moved by the rotation of the carrier screen 43, and is delivered to the carrier screen 44 side over the partition plate 42 by gravity, while the developer around the carrier screen 44 is lower than the lower layer. Gradually, it is pumped up onto the developing sleeve 46b, carried out of the developing container, and dropped into the collecting container 13. By such an action, the developer in the developing container and the developer on the developing sleeve are efficiently collected.

Further, in order to improve the recovery efficiency of the developer, as shown in FIG.
Around the transport screen 43, the developer can be easily moved by curving in a shape similar to the outer diameter of the screen along the line 4, or an opening 42a is formed in a part of the partition plate 42 as shown in FIG. It is also possible to configure that the developer of (4) easily moves toward the transport screen 44. Further, a developing container may be a combination of the embodiments shown in FIGS.

By the way, the developer recovery command may be generated by manually pushing a moded switch for recovering the developer, which is provided on the operation panel of the image forming apparatus main body and corresponds to each developing device. Alternatively, the deterioration of the developer in the developing device may be detected, and the recovery command may be automatically generated according to the detection result. In any case, the rotating body may be rotated so as to move the developing device, which needs to collect the developer, to the developer collecting position B according to the collecting command signal.

Next, an example of a driving method of the developing device will be described with reference to FIGS. 6 and 7. The rotating body 100 is omitted in FIGS. 6 and 7 to avoid complexity.

FIG. 6 is a view of the rotary developing device 4 shown in FIG. 1 as viewed from the back side, and shows the drive connecting portion of the developing device. First, the gears 61A to 61D and the gears 62A to 62D in FIG.
00 is a relay gear, and the input gears 55 and 5
The driving force from 9 is transmitted to the input gears 63A to 63D of each developing device. Incidentally, the gears 61A, 62A, 63A
Are gears corresponding to the developing unit 4Y, gears 61B, 62B and 63B are corresponding to the developing unit 4M, gears 61C, 62C and 63C are corresponding to the developing unit 4C, and gears 61D, 62D and 63D are gears corresponding to the developing unit 4BK. , 63B, 63C, 6
When the driving force is transmitted to any one of the 3Ds, the developing roller of the corresponding developing device, the conveying screw, etc. are driven. Further, the relay gear 61A (61B, 61C, 61D) and the relay gear 62A (62B, 62B, 62C, 62D) and the input gear 63A (63B, 63C, 63D) rotate around the center 0 in accordance with the rotation of the rotator 100 while being in mesh with each other. On the other hand, the input gears 55 and 59 are provided at a predetermined position outside the rotating body 100, and therefore do not rotate with the rotation of the rotating body 100, and the rotating body 10 does not rotate.
Relay gears 61A, 61 moving with the rotation of 0
B, 61C, and 61D are in a stand-by state to mesh with any one of them. Then, as shown in FIG. 7, in the input gear 55, from the gear 51 attached to the drive shaft 50 of the drive motor M2 to the gear 52 → one-way clutch 53 → gear 5
The driving force is transmitted via the second shaft 54. Also,
The driving force is transmitted to the input gear 59 from the gear 51 attached to the drive shaft 50 of the drive motor M2 through the gear 52, the gear 56, the one-way clutch 57, and the shaft 58 of the gear 56. Here, the input gear 55 Is for supplying a driving force for performing the developing operation to the developing device at the developing position A (developing device 4Y in the illustrated example), and the input gear 59 is the developing device at the developer collecting position B ( In the illustrated example, the driving force is supplied to the developing device 4M) to carry out the developer collecting operation.

By the way, the one-way clutch 53 provided between the gear 52 and its shaft 54 and the one-way clutch 57 provided between the gear 56 and its shaft 58 rotate in only one direction. 5
The one-way clutch 53 and the one-way clutch 57 are configured so that the rotational directions for transmitting the rotational force are the same. The one-way clutches 53 and 57 are gears 52 and 56, respectively.
It is provided by being press-fitted inside the
It meshes with 6. Therefore, the gear 52 and the gear 56
The rotation directions of and are opposite to each other, and when one of the one-way clutches 53 and 57 is operating, the other one-way clutch does not transmit the driving force to the shaft. That is, for example, when the drive motor M2 rotates forward, the one-way clutch 53 causes the shaft 5 to move.
Assuming that the driving force is transmitted to the gear 4,
One-way clutch 57 because it rotates in the opposite direction to 2.
Slides on the shaft 58, and the driving force is not transmitted to the shaft 58. Conversely, when the drive motor M2 is rotated in the reverse direction,
Since the one-way clutch 53 slides on the shaft 54 this time, the driving force is not transmitted to the shaft 54, but the driving force is transmitted only to the shaft 58 via the one-way clutch 57. In this way, by switching the rotation direction of the drive motor M2, it is possible to drive only one of the developing device at the developing position A and the developing device at the developer collecting position B by one driving source. . Therefore, at the time of development, by rotating the drive motor M2 forward, only the input gear 55 is rotationally driven, and the developing device 4Y located at the developing position A.
Driving force is transmitted only to the developing device 4M at the developer collecting position B by rotating the driving motor M2 in the reverse direction at the time of developer collecting so that only the input gear 59 is rotationally driven. Will be understood.

In the present embodiment, the drive motor M1 that rotates the rotating body 100 and the drive motor M2 that applies the driving force to the developing device are separate drive sources, but the drive source is not limited to this, and a common drive source is used. It may be.

Here, the contact / separation mechanism of the scraper 12 with respect to the developing roller 46 will be described with reference to FIG.

The scraper 12 is normally in the position shown by the broken line in FIG. 8 due to the biasing force of the spring 74 attached to the main body device (not shown). Then, in accordance with the developer collecting instruction, the solenoid 7
When 73 is energized, the scraper 12 rotates around the shaft 12a against the biasing force of the spring 74 and moves to the position shown by the solid line in FIG. Then, the tip of the scraper 12 is brought into pressure contact with the developing roll 46 of the developing device at the developer collecting position B. Then, when the developing roller and the transport screen of the developing device at the developer collecting position B are rotationally driven by the driving path described in FIGS. 6 and 7, the deteriorated developer in the developing device is collected. It falls into the container 13 (not shown) and is collected.

As described above, the scraper 12 is normally located at the broken line position (when the developer is not collected) and is located outside the rotational movement path of the developing device, so that the desired developing device is set to the developing position. , Rotating the rotating body does not cause any problems.

Next, an embodiment of the present invention will be described with reference to FIGS. 10A and 10B. In this embodiment, the magnetic force generated by the magnetic field generating means is used to move the developer from the developing roller and collect the developer. As shown in FIG. 10A, a collecting roller serving as a magnetic field generating unit faces the developing roller 46 of the developing device at the developer collecting position (the developing device 4M is stopped at the collecting position in this example). 400 are arranged close to each other. The collecting roller 400 is composed of a magnet member 401 having at least N ₃ poles and S ₄ poles, and a sleeve 402 rotatable around the magnet member 401.

When the developer is not collected, the magnetic pole N of the magnet member 401
_{The third} pole is located at a position facing the magnetic pole N ₁ pole of the magnet roller 46 a of the developing roller 46. Therefore, the developing roller 4
A repulsive magnetic field is formed between the 6 and the recovery roller 400 by the N ₁ pole and the N ₃ pole. Therefore, the magnetic developer on the developing sleeve 46b is not attracted toward the collecting roller 400.

On the other hand, when the developer is collected, the magnet member 401 of the collecting roller 400 is set to the magnetic pole N ₁ pole of the magnet roller 46a and the magnet member 401 as shown in FIG. 10B.
The magnetic pole S ₄ is moved so as to face each other. Then, the developing sleeve 46b, the transport screens 43 and 44, and the sleeve 402 are rotated. Then, the magnetic developer carried out from the developing device is attracted to the collecting roller 400 from the developing sleeve 446b by the action of the N ₁ pole and the S ₄ pole. The developer attracted to the collecting roller 400 is conveyed in the illustrated rotation direction of the sleeve 402, reaches the outside of the magnetic field constrained by the magnetic pole N ₃ pole of the magnet member 401, and falls from the sleeve 402 to the container 13 by the action of gravity. In this way, the developer in the developing device can be collected in the container 13.

In order to switch the positions of the magnetic poles N ₃ and S ₄ of the magnet member 401, for example, the shaft 4 to which the magnet member is fixed is fixed.
01a may be moved by a lever or a solenoid (not shown). A scraper may be brought into contact with the collection roller 400 to collect the developer from the collection roller 400 more efficiently.

Although the present invention has been described by taking a color copying machine equipped with a rotary-moving type developing device as an example, the present invention can be applied to other various image forming apparatuses as long as the developing device is of a type that moves. Is also applicable. Further, although the developer collected in the above description is the deteriorated developer, the present invention is not limited to this, and the developer may be temporarily maintained during maintenance of the developing device (for example, inspection of the density detecting element). The developer that can be used may be collected, and it is applicable in this case as well.

(Effects of the Invention) As described above, since the image forming apparatus according to the present invention is configured as described above, there are the following effects.

(1) With respect to a plurality of developing devices, since the developer collecting position is one common position, the space for collecting the developer becomes small, and the collecting work becomes easy.

(2) Since the developer collecting position common to each developing device is different from the developing position, it is possible to prevent the image carrier from being damaged during the collecting.

(3) At the time of collecting the developer, the developer on the developer carrying and conveying member is attracted and removed by magnetic force by the magnetic attraction means which is not in contact with the developer carrying and carrying member, so that the developer carrying and carrying member is prevented from being damaged. it can.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a full-color image forming apparatus showing an embodiment of the image forming apparatus of the present invention. FIG. 2 is a schematic sectional view illustrating the structure of the developing device of the apparatus shown in FIG. FIG. 3 is a schematic cross-sectional view illustrating a developing device in a developer recovery state. 4 and 5 are schematic cross-sectional views illustrating another embodiment of the developing device in the developer recovery state. FIG. 6 is a schematic view illustrating a drive transmission mode for the developing device. FIG. 7 is a schematic view illustrating a switching mode of the driving force for the developing device in the developing position and the developing device in the collecting position. FIG. 8 is a configuration diagram illustrating a drive mode of the scraper. FIG. 9 is a schematic perspective view illustrating the drive mechanism of the rotating body. It is a schematic sectional drawing which shows the other Example of the developer collection | recovery of FIG. 10A and FIG. 10B. 1 ... Photosensitive drum, 4 ... Developing device, 12 ... Scraper, 13 ... Collection container, 46 ... Development roller, 100 ... Rotating body, 400 ... Collection roller, M1, M2 ... Drive motor

Claims (1)

[Claims] 1. An image carrier, a latent image forming means for forming an electrostatic latent image on the image carrier according to image information, a developing container containing a developer, and agitating and moving the developer in the developing container. A plurality of developing devices each having a rotatable stirring member for carrying and carrying a developer in a developing container for carrying and applying the developer to the image carrier, which are common to each developing device. At a developing position, a plurality of developing devices that apply different color developers to the image bearing member, and a plurality of developing devices that are common to the developing position and each developing device, and Developing device moving means for moving along a predetermined path including a developer collecting position different from the position, and the stirring member and the developing device of the developing device positioned at the developer collecting position for collecting the developer inside. Drive means for rotationally driving the agent carrying and transporting member; Magnetic attraction that is opposed to the developer carrying and conveying member, which is rotationally driven by the driving means, of the developing device located at the collecting position with a gap, and magnetically attracts and removes the developer on the developer carrying and conveying member by magnetic force. When collecting the developer in the desired developing unit, the desired developing unit is moved to the developer collecting position, and the driving unit drives the stirring unit and the developing unit of the desired developing unit. An image forming apparatus, wherein a developer carrying member is rotated, and the magnetic attraction means collects the developer in the developing container via the developer carrying member.