JPH09211948A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce space for exchanging developer and to efficiently exchange the developer and replenish toner, without increasing a handling labor and time for exchanging and replenishing work by constituting an image forming device so that the recovery of the developer from a developing chamber is started after the fact that the toner in a container is depleted is detected. SOLUTION: The toner remaining in an integrated type container 10 is reduced when a series of copying operations is repeated and finally, discharging into a carrying pipe 27 is completed. Then, a photointerrupter 38 as a toner presence detecting means detects it that the toner in the integrated type container 10 is depleted. As the toner presence detecting means, not only the photointerrupter but also a piezoelectric sensor arranged in the vicinity of the discharge port, of the container 10 may be used. Then, that the toner does not remain in the container 10 is detected and then, a used developer in a developing unit 54 is recovered into the container 10 for a specified time.

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 laser printer, and more particularly to a developing apparatus in an electrophotographic image forming apparatus for forming an image using a two-component developer composed of carrier and toner. With regard to the above, the toner is replenished as the toner is consumed, and the developer containing the carrier deteriorated with time is replaced.

[0002]

2. Description of the Related Art Conventionally, a two-component developer composed of carrier particles and toner particles which are triboelectrically attached to the carrier particles has been widely used. When development is performed using such a two-component developer, the toner content of the developer is consumed each time the development is repeated, the ratio to the carrier content is reduced, and as a result, the density of the formed image is reduced. . Therefore, the amount of fresh toner corresponding to the amount consumed is replenished to the developer. On the other hand, carrier particles also pose a problem. For example, when it is repeatedly used, the coating material applied to the surface of the carrier particles in order to enhance the triboelectrification property is peeled off and deteriorated as a carrier, and triboelectrification hardly occurs between the carrier and the toner. If uncharged or insufficiently charged toner is used, the image is deteriorated, and further, the toner is scattered, and the inside of the copying machine main body is contaminated. As a developer, the life is generally about several thousand to several hundred thousand sheets.

Therefore, in many machines up to now, the developing unit is periodically taken out, and the deteriorated carrier or developer in the developing chamber is taken out and replaced with a new one, and the developing chamber has reached the end of its life. The developer was completely replaced. In this developer exchange,
The developing device (developing unit) is pulled out from the apparatus main body, the upper lid is opened, the developing device is turned upside down to take out the developer, and a new developer is accommodated in the developing device. This replacement work is entrusted to manual work by a specialized maintenance worker because it involves the removal work of the developing device, but in a device such as a so-called high-speed copying machine in which developer replacement is frequently performed, It is required that the replacement work is easy, and recently,
A cartridge including a collecting device and a developing device for automatically performing the replacement has been put into practical use.

However, in the structure for automatically collecting, a collecting space is required, the size of the entire apparatus is increased, a new developer tank and a collecting container are required, and it is troublesome to manage them. . For example, JP-A-6-1
Japanese Patent Laid-Open No. 9306 discloses a developer containing portion for introducing a stored new developer into a developing device from a developer inlet, and
Disclosed is a developer cartridge having a waste developer storage portion at the bottom for storing the developer from the developing device through the developer recovery port, which eliminates the troublesomeness of the developer replacement. A space for collecting the agent is still necessary. Since the developer in the developing device is replaced each time the life of the developer is changed, the drawback that the image quality is remarkably different immediately before and immediately after the replacement of the developer has not been solved. Furthermore, when replacing with a cartridge, if expensive durable parts are incorporated in the cartridge, such durable parts will also be replaced.

Therefore, in order to obtain stable image quality which is not affected by the life of the developer, for example, Japanese Patent Laid-Open No. 4-66984.
Japanese Patent Laid-Open Publication No. 2003-242242 discloses a configuration in which the number of image formed sheets is counted, new developer is replenished based on the coefficient signal from the counter, and the same amount of deteriorated developer is collected from the developing device. A method of exchanging little by little is disclosed.
When this method is used, the developer contained in the developing device does not reach the entire life by exchanging the developer little by little before reaching the life, and it is possible to maintain a stable fatigue level.

[0006]

However, in the technique disclosed in Japanese Patent Laid-Open No. 4-66984, a space for accommodating a new developer and a space for collecting a deteriorated developer are required respectively, and the size of the apparatus becomes large. If you do not collectively store the amount of developer equivalent to the life of the machine body, it is necessary to replenish the storage container with new developer, which increases the time and effort for users who only replenish toner conventionally. On the contrary, the burden may increase.

In view of the above points, the present invention compresses the space for exchanging the developer as much as possible, and at the same time, efficiently replaces the developer and removes the toner without increasing the labor of the exchange / replenishment work. An object of the present invention is to provide a developing device that can be replenished.

[0008]

In order to solve the above-mentioned problems, according to the present invention, a storage container for storing a two-component developer and a toner in each of the divided spaces, and a means for visualizing a visible image from the storage container. Developer supplying means for supplying a two-component developer to the developing chamber, a toner supplying means for supplying toner from the container to the developing chamber, and a part of the developer contained in the developing chamber is collected in the container. In the developing device configured to supply a developer in an amount corresponding to the amount of the developer collected every time the storage container is replaced to a developing chamber, Toner presence / absence detection means for detecting the presence / absence is provided, and it is configured to start the developer recovery from the developing chamber after detecting that the storage container is out of toner.

It is preferable that the developer collection operation be repeated a predetermined number of times to complete the collection into the storage container. It is also preferable that the toner supply unit and the developer supply unit are combined by the same mechanism.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described based on an embodiment shown in the drawings. FIG. 1 illustrates an image forming engine having a developing device according to the present invention. The configuration of the entire image forming engine is basically the same as that of a conventionally known one, and the charging unit 5
The surface of the photoreceptor 53 is uniformly charged by 0 and the latent image is written by the slit exposure 51 (for analog) or the laser exposure 52 (for digital), and the latent image is visualized by the developing device 54. . The sheet whose timing is aligned with the visible image (toner image) moving along the photoconductor 53 by the registration roller 55 is conveyed on the guide plate 56, and the transfer device 57 transfers the toner image on the photoconductor 53. Then, the charge is removed by the charge removal brush 58 for stable conveyance, and is completely separated by the action of the separation claw 59, and then sent to the fixing device 61 by the transfer belt 60. The conveyed sheet is subjected to heat and pressure action by the heater 62 and the pressure roller 63 to fix the toner image. On the other hand, the residual toner on the photoconductor 53 is removed by the cleaning unit 64.
It is removed and collected by and a new latent image can be formed.
The eraser 6 disposed between the exposure unit and the developing device 54
Reference numeral 5 is for erasing the charge on the surface of the photoconductor 53 so that the toner does not adhere to unnecessary portions on the photoconductor 53. In addition, the paper sensor 6 arranged on the conveyor belt 60.
Reference numeral 6 is for detecting the separation state of the paper at the transfer portion, and prevents paper jamming and winding.

In the image forming engine having such a basic structure, the integrated storage container 10 is connected to the developing device 54 via the supply device 20 and the discharge device 21. here,
The detailed configuration of the integrated storage container 10 is shown in FIG. 2a.
As shown in the figure, the integrated storage container 10 is formed by fitting a first container 1 in the shape of an annular cylinder and a second container 2 concentric therewith. As can be seen in the exploded view of FIG. 2 b, the second container 2 has a protrusion 11 which is inserted into the central space of the first container 1. A protrusion 13 that engages with the inner recess 12 of the first container 1 is formed on the side surface of the protrusion 11, and both containers are fitted together.

Returning to FIG. 2a, both containers are rotated as a unitary container, and in the same direction of rotation, the contents in the first container (here unused developer consisting of toner and carrier) and the second container are rotated.
The contents (here, toner) in the container are discharged to the outlet side, FIG. 2a
In order to convey it to the left side as seen in, convex spirals 4 and 5 are attached to the inner peripheral wall of the container. In addition, in order to reliably discharge the content portion, the region that transitions from the large diameter portion to the small diameter portion of each container (the stepped region of the constricted portion of the container) has a shape that matches the spiral flow of the content discharge. Rake walls 6 and 7 are provided. A common lid 15 having a grip portion 14 is fitted in the discharge ports of both containers so that when the containers are mounted on the developing device 54, they are detached by using, for example, an automatic chuck.

Next, the actual supply of toner and developer will be described with reference to FIGS. 1 and 3a. As described above, the first container 1 of the integrated storage container 10 shown in FIG. 2a is initially filled with a predetermined weight of the unused developer. The second container 2 is filled with toner. The predetermined weight of the developer is understood as the amount of one partial replacement of the developer, and the amount of the developer used in the developing device,
It is determined by the ratio to the amount of toner in the integrated storage container, the degree of deterioration of the developer itself, and the like. Usually, about 10% of the amount of developer used in the developing device is sufficient. The unused developer is the same as the developer that has been used when the developer is replaced by a conventional service person. In some cases, only the carrier may be used.

When a new developer is supplied by exchanging the integrated storage container, the developer in the developing device at the time of the replacement is the same as the new developer supplied from the first container 1, which will be described later in detail. The same amount of used developer has already been collected in the storage container. New integrated storage container 10
When the toner is set on the apparatus main body side, the toner concentration T _c in the developing device is usually lower than the target toner concentration T _cmin . Therefore, immediately after the integrated storage container 10 is set, a toner replenishment signal is sent to the container. In response to this signal, the integrated storage container 10 is rotated in the direction of arrow 40 in FIG. 3a by a drive source (not shown). By the action of the spiral projection 5 (FIG. 2a) provided on the inner peripheral wall of the container, the second
The toner 43 in the container 2 is replenished from the discharge port 24 (FIG. 1). At this time, since the spiral protrusions 4 (FIG. 2a) in the same rotation direction are also provided on the inner peripheral wall of the first container 1, the unused developer 41 in the first container is also discharged through the discharge port as toner is replenished. 23 (FIG. 1) is automatically discharged. That is, the supply of the developer is performed at the same time when the toner replenishing operation is performed. At this time, the amount of the unused developer in the first container is
It is much smaller than the amount of toner in the container, and the fluidity of the developer is usually higher than that of the toner. Therefore, the developer 41 of the developer 41 can be transferred to the developing device 54 much faster than the toner in the second container is depleted. Supply is complete.

In this embodiment, the toner supply and the developer supply are performed under the same rotation of the container, but the spiral protrusions 4 and 5 of each container are attached so that the inclination directions thereof intersect with each other and the development is performed. The toner and the unused developer may be supplied to the container 54 separately by reverse rotation. In this case, the unused developer supply mode is required before starting the toner replenishment.

The unused developer supplied from the discharge port 23 of the integrated storage container 10 and the toner supplied from the discharge port 24 are both fed by the replenishment guide 26.
7 and the conveying screw 2 in the pipe 27
8, the receiving port 3 formed in the upper lid of the developing device 54
It is discharged into the developing device 54 via 0. In this embodiment,
When the toner concentration T _c in the developing unit reaches the target toner concentration T _cmin , the integrated storage container 1 is _placed in the transport pipe 27.
The replenishment operation is adjusted so that the toner discharged from 0 remains.

The unused developer and toner supplied into the developing device 54 reach the first conveying screw 31 disposed immediately below the receiving port 30. The first conveying screw 31
Is for agitating and transporting the developer from the back side to the front side of the drawing, and the second agitating screw 3 paired with the developer is conveyed.
2 is, on the contrary, for stirring and conveying the developer from the front side to the back side of the paper. Under the operation of these agitation screws, the supplied new developer / toner is uniformly mixed with the developer in the developing device 54, and then moves to the developing sleeve 33 side,
A toner image corresponding to the latent image is formed on the photoconductor 53. When a series of copying operations are repeated, the toner remaining amount in the integrated storage container 10 decreases, and finally the discharge to the transport pipe 27 is completely completed. Then, the photo interrupter 38, which is a toner presence / absence detection unit, detects that the integrated storage container 10 is out of toner. The toner presence / absence detection unit is not limited to the photo interrupter, but may be the integrated storage container 1
It may be a piezoelectric sensor arranged near the zero discharge port.
After it is detected that no toner remains in the integrated storage container 10, the used developer in the developing device 54 is collected in the integrated storage container 10 for a predetermined time.

The recovery of this used developer will be described with reference to FIGS. 1 and 3b. In FIG. 1, the developer is collected by the discharging device 21 arranged on the opposite side of the developing device 54 from the side where the supplying device 20 is mounted, on the back side of the paper. When the new developer is supplied as described above, the developer liquid level in the developing device 54 rises. When the stirring screws 31 and 32 are operated, the liquid surface becomes wavy. The used developer spilling to the discharge port 35 is temporarily lifted by the discharge device 21 including a transfer pipe and a transfer screw housed therein at the time of recovery, and slides down in the hopper-shaped recovery guide 36 by its own weight. It is conveyed so as to flow into the integrated storage container 10. The recovery agent 45 that has flowed into the storage container that rotates in the direction of the arrow 44 in FIG. 3B is guided to the bottom by the action of the inner peripheral wall projection 4 (FIG. 1) of the first container 1. The recovery guide 36 is rotatably supported about a vertical rotation shaft 37, and is retracted from the movement range of the lid when the common lid is attached or detached. As described above, the toner density T in the developing device is
Toner is present on the transport pipe 27 when _c is restored to the target toner concentration T _cmin . Therefore, even if the toner is emptied in the integrated storage container 10, the toner is replenished on the transport pipe 27. Since there is toner for use, even in the developer collecting mode, the toner can be replenished into the developing device by driving the conveying screw 28 to perform the copying operation.

Next, the used developer collecting mode will be described with reference to FIG. In the block diagram of FIG. 4a and the flowchart of FIG. 4b, when the toner presence / absence detection means (sensor) detects that the toner in the integrated storage container is used up, the developer is collected. The collection of the developer is started by the CPU at the same time as driving the motor for collecting the developer and turning on the timer. When the timer reaches a set time, an interrupt signal is sent from the CPU to the developer collection motor, and the motor is stopped. Then, the collection is completed.
In this embodiment, the developer is collected even during the copying operation. However, depending on the machine,
During the copy operation, particularly during writing of a latent image and image formation, image unevenness may occur due to the vibration caused by the developer collecting operation. In such a case, it is not preferable to perform the collecting operation during the copying operation. However, if the copying operation cannot be performed during the collecting operation, the copying operation will be interrupted. The recovery of the agent is divided into a predetermined number of times (P times), and the recovery operation is performed for each predetermined time. As can be seen from FIG. 4C, it is determined whether the copy start button is ON, and if it is ON, the copy operation is prioritized, and if it is not ON, recovery is performed for a predetermined time. Since the recovery is divided into several times in a short time, the time for interrupting the copy operation can be extremely shortened.
Here, the target recovery amount for each time is determined by the number of times of division (P) and the recovery time. For interruption, the start button is O
Since it is only N, the collecting operation is not interrupted unless the start button is turned on during the collecting operation.

In the present invention, the timing of collecting the used developer and its operation are important, and it is needless to say that the present invention is not limited to the illustrated embodiment unless it deviates from the basic idea of the present invention.

[0021]

According to the first aspect of the invention, there is provided toner presence / absence detection means for detecting the presence / absence of toner in the integrated storage container, and after detecting that the storage container is depleted of toner, Since it is configured to start collecting the developer from the developing chamber, the toner in the container is used without waste and the developer is collected, which is advantageous in terms of space and the replacement / replenishment work. The developer can be efficiently exchanged without increasing the time and effort.

According to the second aspect of the present invention, the developer recovery operation is repeated a predetermined number of times so that the recovery into the storage container is completed, so that image unevenness due to vibration becomes a problem. Even in such a case, the copy operation and the collection operation can be reasonably adjusted. According to the third aspect of the invention, since the toner supply means and the developer supply means are combined by the same mechanism, the apparatus can be downsized and simplified.

[Brief description of drawings]

FIG. 1 is an overall schematic configuration diagram of an image forming engine including a developing device according to the present invention.

FIG. 2 is a schematic configuration diagram of an integrated storage container, in which (a) shows a connection state of each storage unit while showing a state of a spiral protrusion, and (b) shows an exploded view before the connection. It is shown.

FIG. 3 is a diagram showing a state in the vicinity of a container outlet,
(A) is for supplying developer and toner,
(B) is for collecting the deteriorated developer.

FIG. 4 is an explanatory view showing the concept of collection according to the present invention,
(A) is a block diagram of a part related to collection, (b) is a flowchart when collection is completed by one operation, (c)
Is a flow chart in the case of collecting by repeating operation.

[Explanation of symbols]

 10 integrated storage container 20 supply device 21 discharge device 33 developing sleeve 38 toner presence / absence detection means 53 photoconductor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Sou Kai 1-3-6 Nakamagome, Ota-ku, Tokyo Within Ricoh Co., Ltd. (72) Inori Kiyonori Tsuda 1-3-3 Nakamagome, Ota-ku, Tokyo Shares Inside Ricoh Company (72) Inventor Satoshi Hatori 1-3-6 Nakamagome, Ota-ku, Tokyo Shares Ricoh Company

Claims (3)

[Claims] 1. A storage container which stores a two-component developer and a toner in respective compartments, and a developer supply unit which supplies the two-component developer from the storage container to a developing chamber including a visualizing unit. It has a toner supply means for supplying the toner from the storage container to the developing chamber and a developer collecting means for collecting a part of the developer stored in the developing chamber into the storage container, and collects it every time the storage container is replaced. In a developing device configured to supply a developing chamber with an amount of developer corresponding to the stored developer, a toner presence / absence detection unit for detecting the presence / absence of toner in the storage container is provided, and the toner is stored in the storage container. A developing device configured to start the recovery of the developer from the developing chamber after detecting that there is no longer any. 2. The developing device according to claim 1, wherein the developer collecting operation is repeated a predetermined number of times to complete the collection into the storage container. 3. The developing device according to claim 1, wherein the toner supply unit and the developer supply unit are combined by the same mechanism.