JP3432673B2 - Image forming device - Google Patents

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, which is equipped with a developing device using a two-component developer.

[0002]

2. Description of the Related Art Conventionally, a developing device using a so-called two-component developer composed of charged carrier particles and charged toner particles adhering to the carrier particles in a triboelectrifying manner is considered suitable for obtaining a high quality copy image. Is widely used. When development is performed using such a two-component developer, the toner component of the developer is consumed each time the development is repeated, the ratio to the carrier component decreases, and as a result, the density of the formed image decreases. . Therefore, it is performed to replenish the developer with fresh toner in an amount corresponding to the amount consumed.
The carrier particles also have various problems. For example, when they are repeatedly used, the coating material applied to the surface of the carrier particles in order to enhance the triboelectrification property is peeled off and deteriorates as a carrier.

Therefore, in order to obtain a stable image quality which is not affected by the life of the developer, a method of replacing the developer little by little has been proposed. In this system, the developer can be replaced little by little before reaching the end of its life, and the developer contained in the developing device does not reach the end of its life as a whole, and a stable degree of fatigue can be maintained.

As described above, it is preferable to partially replace the developer, but in this case, it is necessary to always keep the amount of the developer in the developing device at a constant amount. If the developer is partially replaced and the developer is insufficient, the pumping amount to the developing sleeve will be insufficient, resulting in partial insufficient density, uneven density, carrier adhesion and the like. When the developer is excessive,
The driving torque of the developing sleeve and the stirring means increases, the rotation speed slows or stops, and the developer overflows from the developing device, which seriously affects the functions of the peripheral units. Therefore, the recovery amount and the supply amount at the time of partial replacement of the developer must be the same.

Therefore, for example, in Japanese Unexamined Patent Publication No. 4-29271, if the amount of developer used in the developing machine reaches a preset value, a part of the used developer in the developing machine is preset. Disclosed is a developer supplying / discharging mechanism including a means for discharging a predetermined amount and a means for supplying a developer, which is approximately the same amount as the discharged amount, to a developing machine.
In this developer supply / discharge mechanism, specifically, the amount of the developer to be replaced by operating the discharge valve is 20% to 30% of the whole amount.
% Is discharged to the recovery container, and the same amount of new developer is automatically replenished while being monitored by the level sensor. Further, Japanese Patent Laid-Open No. 6-27809 discloses a method of supplying a new developer from a replenishing container so that an increasing amount of the developer overflows into a recovery container and is discarded.

[0006]

However, in the former developer supplying / discharging mechanism, the amount of the developer to be recovered is not fixed, and the same amount as the amount of the developer to be recovered is detected by the level sensor. It is supplied while monitoring, and there is a problem that it is difficult to collect it in accordance with a preset supply amount. Also, in the latter developing method, variations occur due to many factors such as the state of the developing device, that is, the operating state and installation state, or the deviation of the developer due to movement of the device, etc., and recovery is performed according to the preset supply amount. For this reason, if a means for supplying and discharging the developer with high accuracy that matches the amount of the developer to be supplied and discharged and a detection means are provided, the cost increases and the cost becomes high.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus capable of maintaining a constant amount of the developer in the developing device without replacing the developer while replacing a part of the developer. .

[0008]

In order to solve the above problems, the present invention provides an image carrier and a developing device for developing an electrostatic latent image formed on the image carrier with a two-component developer. The
A container for storing replenishment toner to be replenished to the developing device,
A container for supplying the replenishing developer for replenishing the image forming device,
An image forming apparatus having a discharge device for collecting the developer from the image device , wherein the amount of the developer collected from the developing device at a time is a part of the total amount, and the replenishment toner is stored.
The container that holds the replenishment developer and the container that
The integrated container and replenishment toner and replenishment developer
And a supply device for replenishing the image device,
After mounting on the main body of the image forming apparatus, the replenishment by the supplying apparatus
The developer is replenished to the developing device and then consumed for image formation.
Replenishment toner for the toner
Replenishing toner supplied to the imaging device and stored in the integrated container
When the discharge device disappears,
Part of the developer contains the replenishment developer of the integrated container.
A developer amount detecting means for detecting the developer capacity is provided inside the developing device while collecting the developer into the container, and when the developer is collected from the developing device, the discharging is performed according to the output from the developer amount detecting means. The device is operated, and the recovery amount is determined so that the developer capacity in the developing device becomes a predetermined amount.

According to the present invention, the developer amount detecting means and the developer amount detecting means circulate in the developing device.
Developer provided for recovery in the direction of developer flow
It is effective if it is arranged on the upstream side of the discharge port and in the vicinity thereof .

In the present invention, the developer amount detecting means is
It is effective if they are arranged at different positions in the plurality of developing devices.

[0011]

Embodiments of the present invention will be described in detail with reference to the accompanying drawings. An example of the image forming unit of the image forming apparatus according to the present invention is shown in FIG. 1, and the mechanism of the image forming unit is basically the same as a conventionally known one. The image carrier 53 is a drum-shaped photoreceptor, the surface of which is uniformly charged by the charging unit 50, a latent image is written by the laser exposure 52, and the latent image is visualized by the developing device 54. Registration roller 5
The sheet of paper conveyed in time with the visible image through the sheet 5 is sent toward the surface of the photoconductor 53 while being guided by the guide plate 56, and is transferred by the transfer device 57 to the photoconductor 53.
The upper toner image is transferred, and the charge is removed by the charge removal brush 58 and separated from the photoconductor 53. Reference numeral 59 is a photoconductor 5
It is a separating claw that prevents winding around 3. The separated sheet is sent to the fixing device 61 by the conveyor belt 60, and the sheet is subjected to heat and pressure by the heater 62 and the pressure roller 63 to fix the toner image. The residual toner on the photoconductor 53 is removed and collected by the cleaning unit 64, and the charge is removed by the quenching lamp 65, so that a new latent image can be formed. A paper sensor 66 is arranged on the transport belt 60, and the paper sensor 66 is for detecting the separation state of the paper at the transfer portion.

In the image forming section having such a basic structure, the developer-toner integrated cartridge 10 is connected to the developing device 54 via the supplying device 20 and the discharging device 21. Here, the configuration of the developer-toner integrated cartridge 10 is shown in FIG. As shown in FIG. 2A, the cartridge 10 includes a first container 1 in the shape of an annular cylinder that contains a developer in which a toner and a carrier are mixed in such a ratio that they can be used as they are in the developing device. The second container 2 containing the toner for replenishment is concentrically fitted with the second container 2. As can be seen from the exploded view of FIG. 2 (b), the second container 2 has a small-diameter protruding portion 11 that is inserted into the central space of the first container 1. A protruding portion 13 that engages with the inner recess 12 of the first container 1 is formed on the side surface of the projecting portion 11, and the sealing member 3 is attached over the entire circumference of the open end, so that both containers are fitted together. When doing so, it ensures a tight seal between the two containers.

Returning to FIG. 2 (a), both containers rotate as an integral cartridge, and the contents (the developer in the first container and the toner in the second container) respectively accommodated when they rotate in mutually opposite directions. The convex spiral portions 4 and 5 are attached to the inner peripheral wall of the container so as to convey the sheet to the discharge port side which is the left side of the figure.
The convex spiral portions 4 and 5 have mutually opposite inclinations. When the convex spiral portions 4 and 5 rotate the cartridge in one direction, for example, the developer is conveyed to the discharge port side, and the toner is discharged to the discharge port side. When the developer and the toner are conveyed in a direction away from and rotated in the opposite direction, the respective conveying directions of the developer and the toner are reversed.
In order to reliably discharge the contents, the region where each container moves from the large diameter part to the small diameter part (the stepped region of the constricted part of the container) has a scoop with a shape that matches the flow of the contents by each spiral part. Walls 6 and 7 are provided. A common lid 15 having a knob 14 is fitted to the discharge ports of both the containers 1 and 2, and when the container is attached to the developing unit, it is detached using an automatic chuck 39 as described later.

Returning to FIG. 1 again, the first container 1 in the developer-toner integrated cartridge 10 configured as described above.
Developer discharged from the first discharge port 23 and the second container 2
The toner discharged from the second discharge port 24 is discharged into the conveying pipe 27 by the replenishment guide 26, and the conveying screw 28 provided in the conveying pipe 27 causes the developing device to pass through the receiving port 30 of the developing device 54. It is discharged into 54.

The replenished developer or toner reaches the first stirring screw 31 arranged adjacent to the receiving port 30. The first stirring screw 31 stirs and conveys the developer from the front side to the rear side in the drawing, and the second stirring screw 32 paired with the first stirring screw 31 conversely stirs and conveys the developer from the rear side to the front side in the drawing. It is a thing. Under the operation of these stirring screws, the developer in the developing device 54 is uniformly mixed. After that, the developer moves to the developing sleeve 33 side and forms a toner image corresponding to the latent image on the photoconductor 53.

As shown in FIGS. 1 and 5, the developing device 54 is provided with a discharge port 35 adjacent to the end of the second stirring screw 32, and the discharge device 21 is attached to the discharge port 35. Has been. The discharging device 21 discharges a part of the developer in the developing device 54, and the developer passes through the discharging port 35, and is guided by the discharging device 21 including a conveying pipe and a conveying screw housed in the conveying pipe. It is conveyed to the developer-toner integrated cartridge 10 via 36. At this time, the recovery agent that has passed through the discharge port 35 is temporarily lifted by the discharge device 21 so that the recovered developer (recovery agent) is finally easily stored in the cartridge 10, and the recovery agent guide 36 is self-weighted. It slides down and flows into the cartridge. The recovery agent guide 36 is rotatably supported around a vertical rotation shaft 37, and is retracted from the movement range of the lid 15 when the lid 15 is attached or detached.

FIG. 5 is a top view of the developing device 54. Two
By rotating the stirring screws 31, 32 of the book,
The developer circulates as indicated by the arrow in the figure. A developer amount detecting sensor 111 as a developer amount detecting means is provided in the developing device 54, and the developer amount detecting sensor 111 is arranged at a position closer to the upstream side of the developer flow with respect to the discharge port 35. Preferably, in this example, it is installed on the partition plate 113 upstream of the second stirring screw 32 side as viewed from the discharge port 35. A well-known piezoelectric sensor, a photo sensor, or the like is used as the developer detection sensor 111.

The developer and toner are supplied by the developing device 54 when the developer / toner integrated cartridge 10 is set.
The developer contained in the first container 1, which is a part of the developer amount, is supplied to the developing device, and then the toner contained in the second container 2 is supplied according to the consumed toner amount. And
When the toner contained in the second container 2 becomes almost empty, a part of the developer in the developing device 54 is collected and filled in the first container 1.

When the developer is supplied from the first container 1 to the developing device 54, as shown in FIG.
After gripping the knob 14 and pulling the lid 15 in the direction of the arrow to remove it, the cartridge is rotated in the direction of arrow 40. By this rotation, the developer 4 stored in the first container 1
1 passes over the rake wall 6 and is discharged to the conveying pipe 27, and is sent to the developing device 54 by the conveying screw 28. At this time, the toner 43 in the second container 2 is agitated while being pushed back into the container in the direction of the white arrow 42 by the action of the spiral portion of the inner peripheral wall, and the occurrence of the blocking phenomenon is prevented.

To replenish the toner after the developer in the first container 1 is discharged, the toner 4 in the second container 2 is rotated by rotating the cartridge in the direction of the arrow 44 as shown in FIG.
3 is discharged to the transport pipe 27 and sent to the developing device 54 by the transport screw 28. In addition, the developing device 54
When recovering the developer from the
The cartridge is set in the discharge port of the container 1, and the cartridge is rotated in the direction of the arrow 44, which is the same as the toner supply. Then, the recovery agent 45 from the developing device 54 is filled in the first container 1 through the recovery agent guide 36.

By the series of operations as described above, the developer is partially replaced automatically while the toner concentration is kept within a certain range, and the deteriorated developer is collected in the cartridge.

FIG. 6 is a block diagram showing a control system of the image forming apparatus, and the above-mentioned operation is controlled by the control unit 101. The control unit 101 receives an output of a cartridge detection sensor 102 that detects whether the developer-toner-integrated cartridge 10 is mounted or not, and rotates the developer-toner-integrated cartridge 10 or the like.
3, image carrier driving system 104, developing sleeve driving system 10
5. A stirring drive system 10 for driving the stirring means in the developing device
6. The conveying screw drive system 107 for driving the screws in the conveying pipe 27 and the discharging device 21 is operated.
The control unit 101 also includes a toner end sensor 1 that detects the amount of toner remaining in the developer-toner integrated cartridge 10.
When the signal from 08 is input and the toner runs out, a developer recovery mode described later is executed. At this time, the developer recovery amount is controlled according to the output of the developer amount detection sensor 111 installed in the developing device.

FIG. 7 is a flowchart showing the basic control contents performed by the control unit 101. That is, the control unit 1
01 receives a signal from the cartridge detection sensor 102 and determines that the developer-toner integrated cartridge 10 is mounted, the drive systems 103 to 107 shown in FIG.
Is operated to supply the developer to the developing device, and after that, the mode is shifted to the normal mode in which normal image formation is performed. Before the transfer to the normal mode, the drive systems 103 to 107 are operated even after the supply of the new developer in the developer-toner-integrated cartridge 10 is completed and until the stirring is sufficiently performed. Is desirable. After the normal mode is performed, a detection signal is input from the toner end sensor 108, and when it is determined that the toner is exhausted, the developer recovery mode is executed. If the toner is still present, the normal mode is executed until the image formation is completed.

In the flowchart of FIG. 7, as the drive systems 103 to 107 are operated, the developer is supplied to the stirring screw of the developing device by the conveying screw as described above, and is sufficiently stirred inside the developing device. Even if toner that is not sufficiently charged adheres to the surface of the image carrier during stirring, the image carrier rotates and the cleaning device 64
It is prevented from being removed and collected by the above and soiling the inside of the image forming unit. In this way, the toner concentration of the developer in the developing device becomes uniform, and the toner is sufficiently charged.

FIG. 8 is a flow chart showing the basic control contents of the image forming mode. Here, each unit of the image forming unit operates according to its function, and periodically detects an insufficient toner concentration from the output of the toner concentration sensor of the developing device. When it is determined that the toner concentration is insufficient, the cartridge drive system 103 and the conveyance screw drive system 107 are activated, and a predetermined amount of toner is supplied from the developer / toner cartridge 10 integrated.

Further, a flow chart of the developer collecting mode is shown in FIG. The cartridge driving system 103, the agitation driving system 106, and the conveying screw driving system 107 are operated, and a part of the developer circulating inside the developing device is conveyed by the conveying screw of the discharging device 21 to the developer toner integrated cartridge 1
It is discharged inside 0. The control unit 101 monitors the output signal from the developer amount detection sensor 111 installed inside the developing device, and when it determines that the developer amount is less than or equal to a predetermined amount, the cartridge drive system 103 and the stirring drive system 10
6. Stop the conveying screw drive system 107. Therefore, the amount of developer collected can be made equal to the amount of new developer in the first container 1 of the developer-toner integrated cartridge 10.

As described above, in this embodiment, since the recovery means (conveying screw of the discharging device 21) is moved while measuring the storage amount of the developer, the new development in the first container 1 for supplying the recovery amount thereafter. The amount can be the same as the dose. Therefore, even if a part of the developer is replaced a number of times, it is possible to always exhibit a constant developing function without causing an excess or deficiency of the amount of the developer in the developing device.

Further, by installing the developer amount detection sensor on the upstream side of the developer discharge port, the developer amount is accurately detected and discharged without being affected by the developer discharge amount or fluctuation. Can be controlled.

Further, in the present invention, a plurality of developer detecting sensors may be installed at different positions inside the developing device. In the example shown in FIG. 5, in addition to the sensor 111 arranged on the second stirring screw 32 side, a sensor 112 is installed on the first stirring screw 31 side. Then, the control unit 101 receives signals from the two sensors 111 and 112, performs a simple calculation (for example, simple average, weighted average, difference, or calculation of time variation amount thereof), and presets the result. And the discharge amount of the developer from the developing device is compared with the constants.
6. Control and adjust the transport screw drive system 107.

By doing so, the developer capacity level can be detected from a plurality of positions, and the developer amount corrected for the bias and time variation of the developer can be obtained more accurately, and the developer can be recovered accordingly. Since the amount can be controlled, even if a part of the developer is exchanged many times, it is possible to always exhibit a constant developing function without causing an excess or deficiency of the developer amount in the developing device.

[0031]

According to the first aspect of the present invention, since the recovery means is moved while measuring the amount of developer stored, even if a small amount of developer is exchanged many times, the amount of developer in the developing device is excessive. It is possible to exert a constant developing function without causing a shortage.

According to the second aspect of the present invention, since the developing amount detection sensor is installed on the upstream side of the developing agent discharge port, the developing agent amount can be accurately measured without being affected by the discharging amount and fluctuation of the developing agent. Can be detected to control the discharge amount.

According to the third aspect of the present invention, the developer volume level is detected from a plurality of positions, and the developer amount corrected for the bias of the developer and the time variation can be obtained more accurately. Since the recovery amount can be controlled, even if a small amount of developer is partially replaced over a large number of times, the developer amount in the developing device does not become excessive or deficient, and a constant developing function is always exhibited. be able to.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram illustrating an example of an image forming unit of an image forming apparatus according to the present invention.

FIG. 2 is a schematic configuration diagram of a cartridge of the present invention, (a)
Shows the whole after assembly, (b) is an exploded view immediately before assembly.

FIG. 3 is a diagram illustrating a replenishing operation of the cartridge of FIG.

FIG. 4 is an explanatory diagram showing a state in which the toner accommodated in the second container is discharged and supplied, and the used developer is collected.

FIG. 5 is a top view of the developing device.

FIG. 6 is a block diagram showing a control system of the image forming apparatus according to the present invention.

FIG. 7 is a flowchart showing basic control contents performed by a control unit.

FIG. 8 is a flowchart showing basic control contents of an image forming mode.

FIG. 9 is a flowchart showing basic control contents of a developer recovery mode.

[Explanation of symbols]

1 first container 2 Second container 10 Developer toner integrated cartridge 54 developing device 21 Ejector 35 outlet 101 control unit 111,112 Developer detection sensor

Front page continuation (72) Inventor Nobuto Yokokawa 1-3-6 Nakamagome, Ota-ku, Tokyo Stock company within Ricoh (72) Kiyonori Tsuda 1-3-6 Nakamagome, Ota-ku, Tokyo Stock company In Ricoh (72) Inventor Satoshi Hatori 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (56) References JP-A-2-144580 (JP, A) JP-A-63-78182 (JP , A) Japanese Unexamined Patent Publication No. 4-243274 (JP, A) Actual Development No. 1-71770 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 15/08 507 G03G 15/08 112

Claims (3)

(57) [Claims] 1. An image bearing member, a developing device for developing an electrostatic latent image formed on the image bearing member with a two-component developer, and the present invention.
A container for storing replenishment toner to be replenished to the image forming apparatus,
A container for supplying replenishment developer for replenishing to the apparatus,
In an image forming apparatus having an ejecting device for collecting the developer from the device, and the amount of the developer collected from the developing device at one time is a part of the total amount, a container for containing the replenishment toner and a replenishment Store developer
An integrated container that is integrated with the container, and replenishment toner and
And a supply device for supplying replenishment developer to the developing device.
Then, after mounting the integrated container on the main body of the image forming apparatus,
The device supplies the replenishment developer to the developing device,
The replenishment toner for the toner consumed in the subsequent image formation is supplied as above.
The integrated container is replenished to the developing device by a feeding device.
After the supply toner stored in the
Part of the developer in the developing device by the integrated container
A developer amount detecting means for detecting the developer capacity is provided inside the developing device while collecting the replenished developer in the container, and when the developer is collected from the developing device, the developer amount detecting means An image forming apparatus, wherein the discharging device is operated according to an output, and a recovery amount is determined so that a developer capacity in the developing device becomes a predetermined amount. 2. The developer amount detecting means is the developing device.
Provided for recovery in the direction of flow of the developer circulating inside.
The image forming apparatus according to claim 1, wherein the image forming apparatus is arranged on the upstream side of the discharged developer discharge port and in the vicinity thereof . 3. The image forming apparatus according to claim 1, wherein the developer amount detecting means is arranged at different positions in a plurality of the developing devices.