JP2554637B2 - Developing device for wet electrophotographic copying machine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a developing device for a wet electrophotographic copying machine, and particularly 200 to 100 parts by weight of toner carrying liquid.
The present invention relates to a developing device that is replenished with a replenishment toner composed of a high solid content in which a dispersion ratio of toner particles is set to be 0 part by weight.

(Prior Art) As is well known, in a developing device for a wet electrophotographic copying machine, a liquid developer is constituted by toner particles and a toner-carrying liquid in which the toner particles are dispersed, and the liquid developer is applied to a photoreceptor. The toner particles are electrostatically attached to the electrostatic latent image on the photoconductor to perform visible image processing.

An example of the developing device described above will now be described with reference to FIG.

That is, in FIG. 4, around the photosensitive drum 1 which rotates in the direction of the arrow in the figure, a charger 2 for applying a predetermined polarity, an exposure device for generating exposure light 3, an eraser 4, a developing device 5, and a transfer device 6 are provided. And a cleaning device 7 are arranged respectively.

The developing device 5 is arranged close to the photosensitive drum 1. The upper part is provided with a supply nozzle 5a for receiving the supply of the liquid developer, and the lower part is provided with a developing container 5A having a liquid developer recovery port 5b formed therein.

Inside the developing container 5A, a plurality of first and second developing rollers 5B and 5C and a squeeze roller 5D arranged along the peripheral surface of the photosensitive drum 1 are provided.

The first and second developing rollers 5B and 5C are arranged close to the peripheral surface of the photosensitive drum 1 with a gap of about 1 mm, and are rotatable in the direction of the arrow shown in the drawing, that is, in the direction in which the photosensitive drum 1 and the photosensitive drum 1 rotate together. It is provided. The squeeze roller 5D is located below the developing rollers 5B and 5C, comes into contact with the photosensitive drum 1, and rotates in the opposite direction to the developing rollers 5B and 5C.

A scraper 5E is in contact with the peripheral surfaces of the developing rollers 5B and 5C and the squeeze roller 5D described above.

In the vicinity of the developing container 5A, a developer containing a liquid developer composed of a resin, toner particles containing a pigment as a main component, and a toner carrying liquid containing an aliphatic hydrocarbon as a main component in which the toner particles are dispersed is stored. The agent tank 5F is arranged.

In the developer tank 5F, a pumping pump 5G for pumping the liquid developer toward the developing container 5A is arranged, and the tip of the rotary shaft of the pumping pump 5G penetrates into the liquid developer. And has a rotary vane for pumping.

The pumping pump 5G and the supply nozzle 5a of the developing container 5A are connected by a pipe 5H, and the other end of the pipe 5J whose one end is connected to the recovery port 5b of the developing container 5A is in the liquid developer in the developer tank 5F. Infiltrated.

A concentration sensor 5K that detects the concentration of the developer in the developer tank 5F is connected to the pumping pump 5G through a pipe 5L, and the pumping pump 5G is agitated by the pumping pump 5G. A pipe 5M for returning the liquid developer to the developer tank 5F is connected.

In such a developing device, the liquid developer drawn from the developer tank 5F by the drawing pump 5G is supplied to the first developing roller 5B via the supply nozzle 5a. The liquid developer supplied to the first developing roller 5B collects between the scraper 5E and the first developing roller 5B, and is supplied onto the photosensitive drum 1 by the rotation of the first developing roller 5B and at the same time as the first developing roller 5B. The portion remaining on the peripheral surface of the roller 5B is scraped off by the scraper 5E and accumulated between the second developing roller 5C and the scraper 5E, and like the first developing roller 5B, the second developing roller 5C is rotated to rotate the photosensitive member. It is supplied on the drum 1. Then, the developer remaining on the peripheral surface of the second developing roller 5C is scraped off by the scraper 5E and flows down to the lower part of the developing container 5A. At the same time, excess developer remaining on the photoconductor drum 1 is removed from the photoconductor drum 1 by the squeeze roller 5D and flows down to the lower part of the developing container 5A. The developer flowing down to the bottom of the developing container 5A returns to the developer tank 5F via the recovery port 5b and the pipe 5J.

By the way, the toner particles in the liquid developer supplied onto the photosensitive drum 1 from the developer tank 5F through the supply nozzle 5a of the developing container 5A are electrostatically charged to the electrostatic latent image on the photosensitive drum 1. As a result, the content of the developer in the developer tank 5F decreases. Therefore, new toner particles are replenished to the developer tank 5F.

To replenish such toner particles, for example,
An ink type replenishment toner having a mixing ratio of the toner particles and the toner-carrying liquid of 11:89 is used, and the toner particles in the replenishment toner are mixed in the liquid developer to obtain a concentration as a liquid developer. Is designed to stabilize.

However, when the image on the photosensitive drum 1 is, for example, a black solid image having a large area ratio with respect to the original image, the amount of toner particles consumed becomes large, so that the concentration of the liquid developer is stabilized. For this purpose, it is necessary to replenish the replenishment toner to make up for the shortage of toner particles. in this case,
As described above, since the content of the toner-carrying liquid is larger than the content of the toner particles in the replenishing toner, when the replenishing toner is supplied into the liquid developer, the toner-carrying liquid of the toner carrying liquid is The total body volume will inevitably increase. Therefore, in the developer tank 5F, the toner carrying liquid may overflow from the developer tank 5F due to the replenishment of new toner carrying liquid in addition to the remaining toner carrying liquid.

Therefore, conventionally, a sensor 5N for detecting the liquid surface level is provided in the developer tank 5F to regulate the amount of developer stored in the developer tank 5F. However, in such a structure, if a small developer tank is used, for example, the capacity of the tank is small. Therefore, in the case of image processing with a lot of black solid portions, the toner particles are replenished with the toner particles. Since the replenishment of the carried liquid also increases, the stop of the replenishing device by the sensor 5N is accelerated, and it is difficult to secure the developer having a desired mixing ratio in the developer tank.

Therefore, in order to eliminate such an inconvenience, 200 to 1000 parts by weight is added to 1000 parts by weight of the toner-carrying liquid so that the mixing ratio with respect to the toner-carrying liquid can be obtained only by supplying a small amount of toner particles. Therefore, it has been proposed to supply a high solid ink type replenishment toner in which toner particles are dispersed into a developer tank.

However, such high solidity replenishment toner is
Due to its high viscosity, the method of dropping the replenishment toner through the constant liquid surface type supply valve (chicken feed valve) generally used for the toner particle replenishment part to replenish the replenishment toner into the developer tank is the same. The toner particles in the replenishment toner that have fallen from the tank may settle in the lower portion of the developer tank or may be unevenly distributed, resulting in a situation in which a desired degree of dispersion in the developer, that is, a diffusion state cannot be obtained. There was

(Object) In view of the problems of the conventional developing device, an object of the present invention is to favorably disperse the developer in the developer when replenishing a high solid replenishment toner, and to eliminate overflow development of the toner-bearing liquid. The purpose is to obtain a developing device for a wet electrophotographic copying machine.

(Structure) In order to achieve the above object, the present invention provides a liquid developer formed by dispersing toner particles containing a resin or a pigment as a main component in a toner carrying liquid containing an aliphatic hydrocarbon as a main component. The liquid developer is stored in a tank, and the liquid developer is supplied to a developing unit in the vicinity of the photoconductor by a pumping pump located in the tank. In a developing device in which replenishment toner formed by dispersing toner particles is replenished,
A rotary pair inner sealing chamber that accommodates at least the replenishment toner therein, a replenishment unit that replenishes the replenishment toner into the revolving body resealing chamber, and a proximate bottom wall of the revolving body reserving chamber inside the revolving body sealing chamber And a rotating body which disperses the replenishment toner in the liquid developer or in a high-concentration developer which is a replenishing liquid for the liquid developer, and which occupies most of the sealed chamber in the rotating body. It is characterized by that.

 Hereinafter, specific description will be given based on examples of the present invention.

First Embodiment (See FIG. 1) In FIG. 1, reference numeral 50F indicates a developer tank, a part of the developer tank 5F in FIG. 4 is modified to be partitioned by a partition wall 8 and a separation chamber 9 is attached. ing. This developer tank 50
F contains a liquid developer having a concentration that can be directly used for development.

On the other hand, the separation chamber 9 contains the high-concentration developer of medium solidity.

That is, in this example, the high solid ink type replenishment toner is introduced into the separation chamber in advance, and is dispersed in the toner carrying liquid as the mother liquor in this separation chamber so that it can be rapidly dispersed in the developer in the developer tank. When a high-concentration developer of medium solidity is made and the toner concentration in the developer tank decreases and toner replenishment occurs, by replenishing this high-concentration developer to the developer tank, In addition, it solves the problem of poor dispersion that occurs when the ink type replenishment toner is directly replenished to the developer tank. The liquid level in the separation chamber 9 is monitored by the float switch 10, and when the liquid level fluctuates beyond a predetermined upper and lower limit of the liquid level, a warning is displayed on the operation panel of the copying machine. Pump P1 in the liquid in the separation chamber 9
And two rotary pumps, pump P2, are installed.

The pump P1 sucks the liquid in the separation chamber 9 and is provided close to the separation chamber 9 and is connected by a pipe 12 to form a high solid content toner bottle 11 which constitutes a part of the replenishing means.
The high solid ink type replenishment toner accommodated in the pipe is operated according to the action of the pump P3 which constitutes a part of the replenishing means.
Inhale from 12. Then, each of these liquids is stirred and dispersed by the rotating body in the pump casing of the pump P1 that constitutes the sealed chamber in the rotary body, and is discharged into the liquid in the separation chamber 9 through the discharge pipes 13 and 14 to separate the liquid into the separation chamber 9. It contributes to the stirring of the liquid inside and the dispersion of the toner particles. Here, the rotary vanes of the pump P1 are located in the vicinity of the bottom wall of the casing in the pump casing, occupy most of the casing, and the replenishment toner from the high solid content toner bottle 11 is separated into the separation chamber as described above. 9
Dispersed in a high-concentration developer. A pulley is provided on the shaft of the motor M1 that drives the pump P1, and a belt 15 is hung on the pulley. The other side of the belt 15 is wound around a pulley provided on the shaft of the pump P2.

The pump P2 sucks in the liquid in the separation chamber 9, and the concentration sensor S1
It is discharged into the separation chamber 9 via. Further, the flow path is switched by the electromagnetic two-way valve V1 to discharge into the separation chamber 9 via the discharge pipe 16 or discharge into the developer tank 50F via the discharge pipe 17.

The concentration sensor S1 is for detecting the toner concentration in the separation chamber 9. When the concentration is lower than the reference as a high concentration developer having a predetermined medium solidity, the pump P3 is operated based on the output of the sensor. The toner bottle 11 is activated and ink type replenishment toner is supplied to the separation chamber 9 via the pump P3. Then, if the prescribed concentration is obtained, the pump
Operation of P3 is stopped.

Pumps P1 and P2 are normally rotated. Therefore, the pump P1 may perform both the function of stirring the liquid in the separation chamber 9 and the function of stirring and supplying the ink toner.

On the other hand, the pump P2 always fulfills the function of sending the liquid to the sensor S1, and when the liquid is discharged by the discharge pipe 16 to stir the inside of the separation chamber 9, the liquid is supplied to the developer tank 50F through the discharge pipe 17. The case is selectively switched by the electromagnetic two-way valve V1. Switching of the electromagnetic two-way valve V1 is performed by receiving a replenishment signal from the concentration sensor in the developer tank 50F.

In addition to the supply method using a solenoid valve as in the above example, an overflow method is also conceivable.

A mother liquor tank 18 containing the toner-carrying liquid is provided in the upper right part of the separation chamber 9 with the outlet facing downward, and the toner-carrying liquid is automatically replenished to the separation chamber via the chicken feed valve 18V according to the liquid level. Is set to be possible.

In this example, the separation chamber 9 including the pump P1, the pipes 13 and 14, etc. is for dispersing the replenishment toner once in the toner-carrying liquid to form a high-concentration developer and for dispersing it in the liquid developer in the developer tank. , Which constitutes the main part of the dispersion means including the rotating body.

In addition to the above example, the following examples can be applied as the dispersing means.

Second Embodiment (see FIG. 2) FIG. 2 shows a part of a developer tank 50F, which is similar to the developer tank 5F in FIG.

A feature of the embodiment shown in the same drawing is that a replenishment tank containing an ink type toner composed of high solid content is directly connected to a pump chamber of a pumping pump.

That is, in FIG. 2, a pump for pumping a rotary body
65G rotary vane 65G ₁ is the pump chamber 65G as a sealed chamber inside the rotor.
Enclosed in ₂ . Rotary vane 65G ₁ occupies most of the pump chamber 65G _2, and is positioned in the bottom wall vicinity of the pump chamber 65G _2. An inlet port 65G ₃ is bored in the center of the bottom wall of the pump chamber 65G ₂ , and a mesh 70 is attached to the inlet port 65G ₃ so as to cover it, and an inlet pipe is attached to the outside of the bottom wall. One end of 61 is connected.

The other end of this introduction pipe 61 is connected to the supply pump P3, and this pump P3 is connected on the introduction side to the opening 11a of the high solid content toner bottle 11 located downward.

The high solid content toner bottle 11 is held in a funnel-shaped holder 26 and has the opening 11a set downward, and is of an ink type having a content of 200 to 1000 parts by weight with respect to 1000 parts by weight of the toner carrying liquid. Contains replenishment toner.

On the other hand, on the upper wall of the pump chamber 65G ₂ , the developing container 5A (4th
(Refer to the drawing), the end of the pipe 5H connected to the supply nozzle 5a is connected, and the end of the pipe 5M for circulating the liquid developer into the developer tank 50F is connected.

In the vicinity of the inlet 65G _{3 on} the bottom wall of the pump chamber 65G _2, a plurality of intake ports 65G ₄ for taking the developer in the developer tank 50F into the pump chamber are opened.

Since the present embodiment is configured as described above, the pump P3 is operated during the replenishment of the replenishment toner, and the ink type toner in the replenishment high solid content toner bottle 11 is pressure-fed toward the pump chamber 65G ₂ .

At this time, since the rotary blade 65G _{1 of the} pumping pump 65G is also rotating, the ink-type toner is sucked into the pump chamber 65G ₂ , but is filtered by the mesh 70 of the inlet 65G ₃ ,
The size of the particles is reduced and sucked, and the particles are agitated by the rotary blades 65G ₁ to be further miniaturized.

On the other hand, the rotation of the rotary blade 65G ₁ causes the developer tank 50F
Since the developer therein is also sucked into the pump chamber 65G ₂ through the intake port 65G ₄ , the above-mentioned ink type toner is diffused in the developer.

The liquid developer in a state in which the ink type toner has diffused in the developer in this way is pressure-fed toward the developing container 5 through the pipe 5H, and at the same time, the developer tank 50F through the pipe 5M.
Is refluxed in.

In the present embodiment, the developer sent to the developing container 5 by arranging the mesh 75 having a passage area smaller than that of the mesh 70 having the inlet 65G ₃ in the opening to which the pipe 5H is connected. The particle diameter of the toner inside is made fine.

In this embodiment, since the mesh and the rotary vanes of the pumping pump are used to miniaturize the high solids replenishment toner, no special miniaturization means is required. Further, in this embodiment, the ink type toner can be easily diffused well by the simple structure in which the ink type toner supply path is directly connected to the pump chamber of the developer pumping pump.

Third Embodiment (See FIG. 3) In this embodiment, when replenishing toner particles of high solidity, a high solid content toner bottle containing the toner particles is stored in a liquid developer in a developer tank. A discharge member having a plurality of small discharge ports formed on its outer wall is connected to the toner supply device, and the toner particles are pressure-fed to the discharge member by a supply pump used to replenish the toner particles from the toner bottle. It is a thing.

 Hereinafter, this example will be described in detail with reference to FIG.

FIG. 3 shows a developer tank 50F in which the pumping pump 5G in FIG. 4 is omitted for convenience of explanation.

A feature of the embodiment shown in FIG. 3 is that a spiral roller is provided inside the discharge member.

That is, the discharge member 80 is connected to the pipe connected to the pump P3 on the left side in the longitudinal direction in FIG. 3, and has a bottle-shaped cross section.

Further, a plurality of small-diameter discharge ports 80A are formed in the peripheral wall of the discharge member 80.

Inside the ejection member 80, a spiral roller 81 having a spiral blade 81A on the outer peripheral surface and being rotatable is inserted.

The spiral roller 81 is arranged with its axial direction aligned with the longitudinal direction of the discharge member 80, and a drive belt 82 is wound around a pulley portion 81B formed at one axial end. That is,
The peripheral wall of the discharge member 80 constitutes a rotary body sealed chamber that houses the spiral roller 81, the spiral roller 81 is located in the vicinity of the peripheral wall of the discharge member 80 which constitutes the rotary body sealed chamber, and Occupies most.

Since the present embodiment is configured as described above, the pump P3 operates when replenishing the replenishment toner. Then, by the operation of the pump P3, the replenishment toner in the high solid content toner bottle is pressure-fed toward the ejection member 80. At this time, since the spiral roller 81 is also rotationally driven by the drive belt 82, the replenishment toner that has entered the ejection member 80 is not included in the spiral roller 81.
While being crushed by the spiral blade 81A of 81, it is conveyed in the discharge member 80 and discharged from the discharge port 80A.

Therefore, the replenishment toner discharged from the discharge port 80A expands and is diffused into the developer when discharged into the developer tank 50F from the discharge port 80A.

According to the present embodiment, the rotation of the spiral roller 81 can be used to subdivide the toner particles, and the ejection pressure can be increased to promote the expansion and diffusion of the toner particles from the ejection port. It is possible to improve the dispersibility of

(Effects) As described above, according to the present invention, the replenishment toner is continuously and highly efficiently dispersed in the liquid developer in the developer tank by the rotating body in the inner chamber of the rotating body, or is supplied to the liquid developer. It is possible to disperse the high-concentration developer in the liquid developer in the developer tank after dispersing it in the high-concentration developer serving as a replenisher.

Moreover, since it is possible to replenish such high solidity replenishment toner, it is possible to replenish a small amount of developer, so that it is possible to suppress an increase in the toner-carrying liquid and thereby the developer overflows. Can be prevented.

In addition, since it becomes possible to replenish the replenishment toner having a high solidity, it is possible to prevent the dripping of the replenishment toner that has occurred up to now, so that it is possible to prevent the operator's hand and the peripheral portion of the apparatus from being soiled.

[Brief description of drawings]

FIG. 1 is a sectional view for explaining a first embodiment of the dispersing means according to the present invention, FIG. 2 is a sectional view for explaining a second embodiment according to the present invention, and FIG. 3 is a third embodiment according to the present invention. FIG. 4 is a partial sectional view illustrating an example, and FIG. 4 is an end view illustrating an example of a wet electrophotographic copying machine suitable for carrying out the present invention. 9 ... Separation chamber, 65G ... Pumping pump, 80 ... Discharging member, 81 ... Spiral roller, P1 ... Pump.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Yoshio Sato Inventor Yoshio Sato 1-3 Shinmei-do, Nakameisei, Shibata-cho, Shibata-gun, Miyagi Tohoku Ricoh Co., Ltd. (56) Reference JP-A-63-132273 (JP, A) Special Kai 63-109479 (JP, A) JP 63-109480 (JP, A) Actual break Sho 50-76837 (JP, U)

Claims (1)

(57) [Claims] 1. A liquid developer containing a toner particles containing a resin or a pigment as a main component dispersed in a toner carrying liquid containing an aliphatic hydrocarbon as a main component is contained in a developer tank,
While the liquid developer is supplied to the developing unit in the vicinity of the photoconductor by the pumping pump located in the same tank, the toner particles are contained in an amount of 200 to 1000 parts by weight with respect to 1000 parts by weight of the toner carrying liquid. In a developing device in which the replenishment toner is dispersed and replenished, at least the replenishment toner is accommodated in the rotating body sealing chamber, a replenishing unit that replenishes the replenishing toner in the rotating body sealing chamber, and the revolving body sealing chamber. The replenishment toner, which is provided in the vicinity of the bottom wall of the rotating body sealed chamber in the room, is dispersed in the liquid developer or a high-concentration developer that is a replenishing liquid for the liquid developer. A developing device for a wet image forming apparatus, comprising: a rotating body that occupies most of the above.