JPH0442268A - Wet developing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wet developing device employed in image forming apparatuses such as copying machines, printers, and facsimiles.

[Conventional technology]

Conventionally, this type of wet-type developing device includes a developing device which is equipped with a developer supplying member such as a developing roller inside and supplies a developer to the surface of a photoreceptor that is an image bearing member, and a developer supplied to this developing device. A developing device consisting of a developing tank that stores a liquid is known, and this developing tank is placed in the front side of the image forming apparatus where a door that can be opened and closed is provided near the developing device, taking into consideration the following points. has been done. First, the developer tank is designed to collect the developer from the developer and cleaning device so that even when the power to the device is cut off, the developer returns to the tank by gravity. Place it below the device. Second, the developer circulation is 0N10F in synchronization with the main motor's 0N10F
Circulation is not performed during standby, and in a copying machine, after the print button is pressed, the pump operates and the developer is pumped from the developer tank to the developer and cleaning device. Until you pump the
Since developing and cleaning cannot be started, which affects the first copy time, the developing tank is placed as close to the developing device and cleaning device as possible. Thirdly, the condenser liquid container that contains a high toner concentration developer and the mother liquid container that contains a developer such as Isopar (trade name) must be replaced when they are empty, so locate them in a location where they can be easily replaced. Place the developing tank in the

However, a conveyance path for conveying transfer paper, etc. to the photoreceptor is formed directly below the developing device, and because there is little space, it is not possible to increase the capacity of the developing tank, and the amount of developer that can be stored There was a problem that the life of the developing solution was shortened.

In addition, since the developing tank is placed on the front side of the image forming apparatus on the conveyance path that conveys the transfer paper, etc. to the photoreceptor, when taking out the jammed transfer paper, etc. on the conveyance path, the developer tank, etc. There was also a problem that the container for the nurse liquid and the mother liquid container were obstructive.

Therefore, in order to solve these problems, the inventor of the present invention has developed a developing device that supplies a developing solution consisting of toner and a developer to an image bearing member, a first developing tank that stores the developing solution, and a first developing tank that stores the developing solution. He invented a wet-type developing device that has a second developing tank that is provided separately from the developing tank and is supplied with a high-toner concentration developer and a developer, and filed a patent application. FIG. 1 is a schematic configuration diagram of a copying machine that employs a wet developing device according to an embodiment of the patent application, viewed from the front. In this wet type developing device, a small tank 72 which is a first developing tank is used.
Since the large tank 71, which is the second developing tank, and the large tank 71 are separated from each other, the small tank 72 is placed close to the developing device 7 and the cleaning device 13, considering the influence on the first copy time, while the large tank 72 is placed close to the developing device 7 and the cleaning device 13. The tank 71 can be placed at the bottom of the copying machine, where there is a relatively large amount of space, so by making the large tank larger than that of conventionally known developing devices, the lifespan of the developer can be extended compared to conventional developing devices. Furthermore, if the small tank is made smaller and the location is taken into consideration, this small tank does not become an obstacle when taking out jammed transfer paper or the like.

[Problem to be solved by the invention]

However, when stopping the supply of the developer to the developing device 7, the supply of the developer from the small tank 72 to the developing device 7 is stopped, and the developer is not supplied from the large tank 71 to the small tank 72. If the supply is stopped at the same time, the developer in the small tank 72 will run out and the developer will be exhausted, and the developer will not be able to complete the development until the developer from the large tank 71 reaches the small tank 72 when the next development starts. There was a problem that there was a possibility that the developer supplied to the container 7 would be insufficient. The reason is that the small tank 72
supplying the developer from the developer to the developer 7 and the large tank 71.
The developer in the small tank 72 is supplied to the developing device until the developer from the large tank 71 reaches the small tank 72. During this period, the developer in the small tank 72 continues to decrease, and after the developer from the large tank 71 reaches the small tank 72, the amount of developer supplied from the large tank 71 to the small tank 72 and the small tank change. This decrease is recovered by the difference between the amount of developer supplied from 72 to the developer 7 (the former is larger), but when the image forming operation is short (for example, when only one copy is being made) This is because this recovery may be insufficient in some cases.

In this way, even when the image forming operation is short, in order to sufficiently recover the amount of developer in the small tank 72, the amount of developer supplied from the large tank 71 to the small tank 72 must be reduced by reducing the amount of developer supplied from the large tank 71 to the small tank 72.
From the viewpoint of recovering the amount of developer in this small tank 72, it may be possible to make it sufficiently large compared to the amount of developer supplied from No. 2 to the developing device, but increasing the size of the supply means (pump or pump drive motor) will occur.

The present invention has been made in view of the above-mentioned problems of the prior art, and its objects are to provide a developing device for supplying a developing solution consisting of toner and developer to an image bearing member; A first developer tank that stores the developer supplied to the first developer tank, and a second developer tank that stores the developer supplied to the first developer tank and is supplied with a high toner concentration developer and a developer, respectively. It is an object of the present invention to provide a wet type developing device capable of sufficiently recovering the amount of developer in a first developing tank even when an image forming operation is short.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a developing device that supplies a developing solution consisting of toner and a developer to an image bearing member, a first developing tank that stores the developing solution supplied to the developing device, and a first developing tank that stores the developing solution supplied to the developing device. In a wet type developing device that stores a developer to be supplied to a first developer tank and includes a second developer tank that is supplied with a high toner concentration developer and a developer, the developer is supplied to the developer. In the case of stopping, after stopping the supply of the developer from the first developer tank to the developing device, the supply of the developer from the second developer tank to the first developer tank is stopped. It is something.

[Effect]

In the present invention configured as described above, a first developing tank and a second developing tank are provided which are separated from each other, and the first developing tank is cleaned by cleaning the developing device and cleaning in consideration of the influence on the first copy time. In addition to placing it in a position close to the device, the high toner concentration developer and developer are supplied to the second developer tank, and thereby the first developer tank is equipped with a container containing the high toner concentration developer and developer. On the other hand, the second developing tank can be placed in a location with a relatively large amount of space, thereby making it possible to increase the size of the second developing tank. When starting to supply developer to the developer, it is necessary to supply developer directly from the first developer tank to the developer until the developer from the second developer tank reaches the first developer tank. With this, it is possible to quickly start the image forming operation, and when stopping the supply of developer to the developing device, the supply of developer from the first developing tank to the developing device is stopped, while the second developing tank is stopped. The developer continues to be supplied from the developer tank to the first developer tank, so that the image forming operation is short and the amount of developer in the first developer tank is reduced when the supply of developer from the first developer tank to the developer is stopped. Recovers the amount of developer in the first developer tank even when it is decreasing,
After that, the supply of developer from the second developer tank to the first developer tank is stopped.

〔Example〕

An embodiment of the present invention will be described based on FIGS. 1 to 3. In this embodiment, when stopping the supply of developer to the developing device in the copying machine shown in FIG. After a certain period of time has passed, the supply of developer from the large tank 71, which is the second developing tank, to the small tank 72 is stopped.

First, the overall outline of the copying machine will be explained using FIG. 1.

A document on a contact glass 1 is irradiated with an illumination device 2, and the reflected light is transmitted through a scanning mirror 3 and a lens 4 to an image carrier that has already been uniformly charged by a corona discharger 5, which is a negative charger. The image is projected onto a certain drum-shaped photoreceptor 6, thereby forming an electrostatic latent image on the photoreceptor 6''. This electrostatic latent image is turned into a toner image by being supplied with a developer by a developing device 7 provided on the right side of the photoreceptor 6. This toner image is conveyed from a paper feed section 8 and transferred to a registration roller 9. The transfer charger 10 transfers the image onto the transfer paper conveyed to the surface of the photoreceptor 6 at the appropriate timing. The transfer paper on which the toner image has been transferred is separated from the photoreceptor 6 by a separation roller 11, passes through a fixing device 12, and is discharged outside the machine as copy paper.

On the other hand, the residual toner on the photoconductor 6 after transfer is removed by a cleaning device 13 provided on the left side of the photoconductor 6, and the residual charge is eliminated by a static elimination lamp 14, and then the negative charger 5 charges the photoconductor 6. be prepared for.

Note that the front of the copying machine below the optical system consisting of the illumination device 2, scanning mirror 3, lens 4, etc. is covered by an openable/closable door (not shown), and by opening this door, Each device around the photoreceptor 6, the entire transport path, and even the developing tank at the bottom of the copying machine can be seen from the front.

Next, the developing device will be explained.

The developing device of this embodiment has a large tank 71 installed at the bottom of the copying machine, which is an enlarged version of the developing tank in which the condenser liquid container and the mother liquid container are installed in the conventionally known developing device. A small tank 72, which is a new developing tank smaller than a conventionally known developing tank, is placed in the position where the developing tank was located in the developing device, and is equipped with an internal developer pump 72a and stores the developer. This is what I did.

The large tank 71 is provided with a condensation liquid container 71a, a condensation liquid replenishing device 71b, a fi degree sensor 71c, a mother liquid container 71d, and a pump 71e. The concentration sensor 71b is connected to the concentration sensor 71, which is installed in the tank at a position where it is always submerged in the developer.
When the developer concentration falls below the set value in response to the signal c, the solenoid is suction driven to open the valve of the condenser liquid container 71, which is installed upside down on the upper lid of the tank 71, which is normally closed by a spring. It is opened by pushing the lever and replenishes high toner concentration developer.

The mother liquid container is also installed upside down on the upper lid of the same tank, and when the amount of developer decreases and the level of the developer in the tank falls below the reference level, the developer discharge port communicates with the atmosphere and It is a chicken field valve that replenishes the developer inside the same tank. Pump 71e installed in the same tank
pumps up the developer stored in the tank and supplies it to the small tank 72 via the developer supply pipe 71f.

Further, the lower end of a developer recovery pipe 71g whose upper end communicates with the lowermost parts of the developing device 7 and the cleaning device 13 and the overflow lower 2b of the small tank 72 is connected to the upper lid of the large tank 71.

The small tank 72 is arranged on the front side of the conveyance path that conveys the transfer paper to the photoreceptor 6, the upper end of the developer supply pipe 71f from the large tank 72 is connected to the upper lid, and the overflow lower 2b is connected to the upper part of the side wall. A pump 71a is provided inside. Here, the height of the overflow lower 2b in the small tank 72 is such that the developer continues to be sent from the small tank 72 to the developing device 7 and the cleaning device 13 until the developer reaches the small tank 72 from the large tank 71. The small tank 72 is configured to store the amount of developer required for the purpose.

The pump 72a has a developer supply pipe 72C272d.
The developer is pumped up and supplied to the developing device 7 and the cleaning device 13 through the pump 71 and the cleaning device 13, respectively, and the pumping flow rate is the same as the flow rate of the pump 71e in the large tank 71 to the small tank 72, or , is set slightly smaller.

Further, both the large tank 71 and the small tank 72 have a developer stirring device (not shown), and pumps 7], e, 7
This is driven in synchronization with the ON/○FF of 2a to prevent unevenness of toner in the developer.

The pump 72a inside the small tank 72 is powered by the main motor 7.
The pump 71e in the large tank 71 is driven by a pump drive motor 7]-h that is separate from the main motor 73, and each motor 71h, 73 is driven by a chain, gear, belt, etc. As shown in the relay 201
, 202 to the CPU 203 and to a 100 volt AC power supply 204, respectively. Also, CPU2
A print button 205 is also connected to 03.

In the above configuration, the developer supply operation will be explained using FIG. 3.

When the print button 205 is pressed, the main motor 73 and the pump drive motor 71h of the copying machine are turned ON (step 1), thereby driving both the pumps 71e and 72a, and the pump 71e inside the large tank 71 The developer mixed in the small tank 72 is pumped up and supplied to the developing device 7 and the cleaning device 13 by a pump 72a in the small tank 72, and the developer is pumped up and supplied to the developing device 7 and the cleaning device 13. The developer used for cleaning and the developer that overflowed in the small tank 72 is collected by its own weight into the large tank 71 via the developer recovery pipe 71g. Copy (copy operation)
When (step 2) is completed, turn the main motor 73 to 0F.
FL (Step 3), which causes the pump 72a to stop, while the pump drive motor 71h continues to be ON for a predetermined set time t (Step 4).
Since the pump 71e continues to supply the developer from the large tank 71 to the small tank 72, the copying time is short, and when the supply of developer from the small developer tank 72 to the developer 7 and cleaning device 13 is stopped, the contents of the small developer tank 72 are Even when the amount of the developer decreases so that the liquid level of the developer becomes lower than the overflow lower 2b, the amount of developer in the small tank 72 is restored by supplying the developer from the large tank 71, After the set time has elapsed, the pump drive motor 71h is turned off (step 5). During this time, the developer remaining in the developing device 7 and the cleaning device 13 is collected by its own weight into the large tank 7 via the developer recovery pipe 71g, but the overflow lower 2b in the small tank 72
The developer below this remains in the same tank 72 as it is. Thereby, even during the next copying, the developer can be supplied from the small tank 72 to the developing device 7 and the cleaning device 13 until the developer from the large tank 71 reaches the small tank 72.

In this embodiment, a large tank 71 equipped with a condenser liquid container 71 a and a mother liquid container 71 d is placed apart from the vicinity directly below the developing device 7 , and the transfer paper is conveyed from the tank 71 to the photoreceptor 6 . Since the developer is supplied to the small tank 72 disposed on the front side of the conveyance path, the compactor liquid container 71a and the mother liquid container 7 are stored in the small tank 72.
1d, and the tank 72 can be made smaller without considering the lifespan of the developer, so it is easy to remove jammed transfer paper, etc. from the conveyance path directly below the developer 7. In addition, a conventional developer tank does not get in the way. In addition, the small tank 72 is arranged on the opposite side (rear side) of the front door of the copying machine with respect to the conveyance path of the transfer paper, and accordingly, each of the developer supply pipes 71f, 72c, 72d and the developer recovery pipe 71g If the piping is installed on the back side, the small tank 72,
The developer supply pipes 71f, 72c, 72d and the developer recovery pipes 7] and 7g do not get in the way at all.

〔Effect of the invention〕

As described above, according to the present invention, even when the image forming operation is short, it is possible to sufficiently recover the amount of developer in the first developer tank, so there is a shortage of developer in the first developer tank. This has the excellent effect of preventing the occurrence of a situation in which the developing solution supplied to the developing device becomes insufficient when the next development starts.

Further, there is no need to increase the size of the developer supply means from the second developer tank to the first developer tank just to prevent the developer solution in the first developer tank from becoming insufficient.

[Brief explanation of drawings]

1 to 3 are drawings for explaining one embodiment of the present invention, in which FIG. 1 is a schematic configuration diagram of a copying machine that employs the wet developing device of this embodiment, viewed from the front, and FIG. The figure is a circuit diagram showing the connection state between the CPU and equipment related to developer supply, and FIG. 3 is a flowchart of control related to developer supply.

Claims (2)

[Claims] (1) A developing device that supplies a developer consisting of toner and a developer to an image carrier, a first developing tank that stores the developer that is supplied to the developing device, and a developer that is supplied to the first developing tank. In a wet type developing device equipped with a second developing tank that stores liquid and is supplied with a high toner concentration developer and a developer, when stopping the supply of the developer to the developing device, the first developing A wet type developing device, wherein the supply of developer from the second developer tank to the first developer tank is stopped after the supply of developer from the tank to the developer is stopped. (2) The supply of developer from the second developer tank to the first developer tank is stopped after a certain period of time has passed after the supply of developer from the first developer tank to the developing device is stopped. The wet developing device according to claim (1).