JP2002296913A - Liquid supply device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printer which resolves the problem that the cost is raised and a device is made large-sized by providing a supply pump for exclusive use for each of a supply developer and a liquid carrier and resolves the problem that it is difficult due to remaining liquid in a discharge flow passage to adjust the concentration of the liquid developer, without restrictions on layout of the supply pump 4. SOLUTION: A liquid supply device is provided with a first flow passage F1 connected to one port of the supply pump 4, a second flow passage F2 which is branched from the first flow passage to reach a developer storage part 2, a third flow passage F3 which is branched from the first flow passage F1 to reach a second tank 135 of a developing unit, a first motor-driven three-way valve 11 which switches liquid flow from the first flow passage F1 to the second flow passage F2 or the third flow passage F3, a fourth flow passage F4 connected to the other port of the supply pump 4, a fifth flow passage F5 which is branched from the fourth flow passage to reach a carrier storage part 3, a sixth flow passage F6 which is branched from the fourth flow passage F4 to reach the second tank 135, a second electric three-way valve 21 which switches liquid flow from the fourth flow passage F4 to the fifth flow passage F5 or the sixth flow passage F6, and a control part which switches the rotation direction of a motor 4a of the supply pump 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid supply device for supplying a supply developer or a liquid carrier to an agent storage section of a developing device, and to an image forming apparatus using the liquid supply device, such as a copying machine, a facsimile, or a printer. It is.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus for forming an image by using a liquid developer, an undeveloped developer remaining on a developer carrier (for example, a developing roller) of the developing device, a latent developer after a transfer process, and the like. There is a known type that recovers a transfer residual developer remaining on an image carrier (for example, a photosensitive drum) and returns the developer to a developer reservoir in a developing device.

In general, the above-mentioned undeveloped developer and untransferred developer have a different concentration from the liquid developer before use.
When the liquid developer is returned to the agent storage section in the developing device, the concentration of the liquid developer before use stored therein is changed. For this reason, in the conventional image forming apparatus for returning the undeveloped developer and the untransferred developer to the agent reservoir, the liquid supply device appropriately supplies the liquid carrier or the high-concentration supply developer to the liquid developer in the agent reservoir. As a result, the concentration is stabilized.

[0004]

By the way, the above-mentioned liquid supply device is provided with a supply pump for conveying a liquid carrier and a supply developer, but the supply developer and the liquid carrier are respectively dedicated to the supply pump. If this is provided, the cost and the size of the device will increase.

[0005] Therefore, as shown in FIG.
And a liquid carrier flow path from the carrier tank are merged by a switching three-way valve 201, and both liquids are supplied to the agent reservoir by a supply pump 4 disposed downstream of the merge point. 200 could be supplied

However, in such a configuration, both liquids flow in the discharge flow path downstream of the supply pump 4, so that the supply developer is diluted by the residual liquid in the discharge flow path, or the liquid carrier is supplied to the liquid carrier. It becomes difficult to adjust the concentration of the liquid developer in the agent reservoir 200 by mixing a developing substance such as toner. Therefore, in order to suppress such difficulties, the supply pump 4 should be connected to the developer reservoir 20 of the developing device as much as possible.
The layout of the supply pump 4 is restricted, for example, when it is necessary to shorten the discharge flow path closer to zero.

SUMMARY OF THE INVENTION The present invention has been made in view of the above background, and has as its object to increase the cost and the size of the apparatus by providing dedicated supply pumps for the supply developer and the liquid carrier. Is eliminated, and
An object of the present invention is to provide a liquid supply apparatus and an image forming apparatus which can eliminate the difficulty of adjusting the concentration of a liquid developer due to a residual liquid in a discharge flow path without restricting a layout of a supply pump.

[0008]

In order to achieve the above object, the present invention is directed to an agent container for storing a supply developer containing a developing substance and a liquid carrier, and a carrier for storing a liquid carrier. A liquid supply device including a storage section and a supply pump for supplying the supply developer and the liquid carrier in the carrier storage section to an agent storage section of a developing device, the liquid supply device being connected to one port of the supply pump; A first flow path, a second flow path branched from the first flow path to the agent storage section, a third flow path branched from the first flow path to the agent storage section, and a liquid flow through the first flow path. A first switch between the second flow path and the third flow path
Switching means, fourth connected to the other port of the supply pump
A flow path, a fifth flow path branched from the fourth flow path to the carrier accommodating portion, a sixth flow path branched from the fourth flow path to the agent storing section, and a liquid flow through the fourth flow path. A second switching means for switching between the five flow paths and the sixth flow path, and a transport direction switching means for switching a liquid transport direction by the supply pump are provided.

In this liquid supply device, the supply developer and the liquid carrier can be individually supplied to the agent reservoir by one supply pump. Specifically, as shown in FIG.
The first switching means 10 secures a path toward the supply pump 4 via the first flow path F1 and the agent storage section from the supply pump 4 via the fourth flow path F4 and the sixth flow path F6. The route to 200 is secured by the second switching means 20. Then, the supply pump 2 controls the first flow path F1.
The supply developer is discharged into the fourth flow path F4 while sucking the liquid, so that the developer for supply is supplied to the developer container 2, the second flow path F2, and the first flow path F4.
The first, fourth and sixth flow paths F4 and F6 are supplied to the agent reservoir through the agent supply paths. On the other hand, when supplying the liquid carrier in the carrier accommodating section to the agent storing section 200, the carrier accommodating section 3, the fifth flow path F5, the first switching section 10 and the second switching section 20, as shown in FIG. While securing the carrier supply path of the fourth flow path F4, the first flow path F1, and the third flow path F3, the liquid transport direction by the supply pump 4 is switched to the reverse direction by the transport direction switching unit. In such a configuration, the sixth flow path F6 is used as a discharge flow path downstream of the supply pump 4, but only the supply developer flows here. Further, the third flow path F3 is also used as a discharge flow path on the downstream side of the supply pump, but here only the liquid carrier flows. That is, only the liquid carrier remains in the third flow path F3 which is the discharge flow path, and only the supply developer remains in the sixth flow path F6 which is the discharge flow path. Therefore, no matter how long these discharge channels are made, the residual liquid in the discharge channels does not adversely affect the concentration adjustment of the liquid developer in the agent storing section 200. In addition, since the first flow path F1 and the fourth flow path F4 are used as a common flow path through which the developer for supply and the liquid carrier flow, there is a possibility that the liquid in the inside may adversely affect the density adjustment. The adverse effect can be effectively suppressed by shortening the common flow path as much as possible. Even if the common flow path is shortened in this way,
The third flow path F3 and the sixth flow path F6, which are the discharge flow paths, can be freely lengthened, so that the layout of the supply pump 4 is not restricted.

A second aspect of the present invention is the liquid supply device according to the first aspect, wherein the switching of the flow path by the first switching means or the second switching means is delayed from the start of driving of the supply pump. Is what you do.

In this liquid supply device, the second switching means 2 is switched from the state in which the agent supply path as shown in FIG.
While the switching of the flow path by 0 and the driving of the supply pump 4 in a state where the transport direction is switched in the reverse direction are started, the switching of the flow path by the first switching means 10 is performed later than these. Then, by delaying in this manner, the supply developer in the common flow path (F1, F4) is returned to the second flow path F2 as shown in FIG. From the second flow path F2.
It is possible to perform the flow path switching by the first switching means 10 at the timing when the flow returns to. Conversely, while returning the liquid carrier in the common flow path to the fifth flow path F5, the supply developer is fed from the first flow path F1 side into the common flow path, and the liquid carrier is transferred to the fifth flow path F5. It is possible to perform the flow path switching by the second switching means 20 at the timing of returning to the above. In such a configuration, the supply developer in the common flow path is transferred to the third flow path F
3, and the liquid carrier in the common flow path is mixed with the supply developer in the sixth flow path F6, thereby suppressing the adverse effect on the density adjustment caused by the mixing. Can be reduced.

According to a third aspect of the present invention, in the liquid supply device of the first aspect, the first switching means or the second switching means includes a check valve for stopping a reverse flow in the second flow path or the fifth flow path. ,
And a check valve for stopping the backflow in the third flow path or the sixth flow path.

In this liquid supply apparatus, for example, when a first switching means having a check valve for stopping a backflow in the second flow path and a check valve for stopping a backflow in the third flow path is used. When the supply pump is driven in a state in which the liquid transfer direction is switched from the first flow path side to the fourth flow path side, the former check valve is automatically opened by the liquid flow in the first flow path and the latter is opened. Close the check valve. By opening and closing such a check valve, liquid flow between the second flow path and the first flow path is allowed, and liquid flow between the third flow path and the first flow path is prevented. On the other hand, when the supply pump is driven in a state where the liquid transport direction is switched to the opposite direction, the former check valve is automatically closed by the liquid flow in the first flow path, and the latter check valve is opened. .
By opening and closing such a check valve, liquid flow between the second flow path and the first flow path is prevented, and liquid flow between the third flow path and the first flow path is allowed. Therefore, the flow path can be switched without connecting a special driving means to the first switching means. Further, a second check valve having a check valve for stopping backflow in the fifth flow path and a check valve for stopping backflow in the sixth flow path
Even when the switching means is used, the flow path can be switched without connecting a special driving means to the second switching means.

According to a fourth aspect of the present invention, in the liquid supply device of the first, second or third aspect, the seventh flow path toward the agent container is connected to the fourth or sixth flow path, and the connection is established. The liquid flow through the fourth flow path portion on the supply pump side from the position is switched between the fourth flow path portion and the seventh flow path on the second switching means side, or the liquid flow from the connection position A third switching means for switching the flow of the liquid to and from the sixth flow path on the second switching means side between the sixth flow path part and the seventh flow path on the agent storage section side is provided. Is what you do.

In this liquid supply device, the supply developer in the fourth flow path or the sixth flow path is returned to the agent storage section via the seventh flow path, whereby the supply developer in the agent storage section is returned. Can be stirred by convection. With this configuration, even if the concentration of the supply developer is not uniform due to the sedimentation of the developing substance in the developer container, the developer can be made uniform by stirring.

According to a fifth aspect of the present invention, in the liquid supply apparatus according to the first, second, third or fourth aspect, a check valve is provided in a portion of the fifth flow path at a predetermined distance from the second switching means. It is a feature.

In this liquid supply device, carrier contamination due to the backflow of the developing substance in the fifth flow path can be suppressed for the following reason. That is, both the developer for supply and the liquid carrier flow in the second switching means constituted by a combination of a check valve and a three-way valve. The agent storage section 2 is formed by the agent supply path as shown in FIG.
When the supply developer is supplied to the second switching unit 2
The supply developer is contained in the liquid carrier in the fifth flow path F5 when the flow path is switched. Even if mixed as described above, the liquid carrier is conveyed from the fifth flow path F5 to the second switching means 20 after the flow path is switched, so that the mixed supply developer and the developing substance contained therein are removed from the fifth flow path F5. 5 flow path F5
It is unlikely that there will be backflow inside. However, in the connection portion between the fifth flow path F5 and the second switching means 20, the flow path diameter is often varied due to the presence of the connection means and the like, and an obstacle to the liquid flow is often present, so that a local In some cases, a convection portion of the liquid carrier may be formed. When the mixed supply developer is drawn into the convection section and the development substance is convected until the end of the carrier supply, the result is that the developer remains in the fifth flow path F5. The remaining developing substance is provided such that its specific gravity is lighter than that of the liquid carrier, or even if it is heavier, the fifth flow path F5 is provided with a downward gradient toward the carrier accommodating portion (in the example shown in FIG. In this case, the current flows backward toward the carrier accommodating section 3 until the next carrier supply is started. Therefore, in the present liquid supply apparatus, a check valve is provided in the fifth flow path, and the back flow of the developing substance is stopped at the position of the check valve so as to suppress carrier contamination caused by the back flow. I have.

According to a sixth aspect of the present invention, in the liquid supply apparatus of the fifth aspect, the supply amount of the liquid carrier per carrier conveyance by the supply pump is set between the second switching means and the fifth flow path. It is characterized in that it is larger than the liquid amount between the check valve.

In this liquid supply device, the developing material whose backflow has been stopped by the check valve in the fifth flow path can be returned to the second switching means when the carrier is supplied. The resulting carrier contamination can be more reliably suppressed.

According to a seventh aspect of the present invention, there is provided a latent image carrier for carrying a latent image, a latent image forming means for forming a latent image on the latent image carrier, and a liquid developer containing a developing substance and a liquid carrier. An image forming apparatus comprising: a developing device for developing a latent image on the latent image carrier using the developing device; and a liquid supply device for supplying a liquid developer and a liquid carrier to a developer reservoir of the developing device. The invention is characterized by the use of the first, second, third, fourth, fifth or sixth aspect.

In this image forming apparatus,
The liquid developer concentration of 2, 3, 4, 5, or 6 can be satisfactorily adjusted by eliminating the difficulty of adjusting the concentration of the liquid developer due to the residual liquid in the discharge flow path. Thus, the image density can be stabilized.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to an electrophotographic printer as an image forming apparatus will be described below. First, a basic configuration of the printer according to the present embodiment will be described. FIG. 4 is a schematic configuration diagram of the printer. In the figure, around a photosensitive drum 51 as a latent image carrier, a liquid supply device 1, a charging unit 52,
A developing unit 100 as a developing device, an intermediate transfer drum 53, a drum cleaning unit 54 for cleaning the photosensitive drum 51, and the like are provided. On the right side of the intermediate transfer drum 53 in the figure, a transfer roller 55 that is in contact with the transfer roller 55 and forms a secondary transfer nip having a predetermined width is provided.

The photosensitive drum 51 is driven to rotate at a constant speed in a direction indicated by an arrow (clockwise) in FIG. After the peripheral surface is uniformly charged by the charging unit 52 with the rotation, the writing light LB based on the image information is irradiated and imaged by an optical writing unit (not shown) to carry the electrostatic latent image. I do. The electrostatic latent image is developed by the developing unit 100 to become a visible image using a liquid developer, and then moves to a position where the electrostatic latent image comes into contact with the intermediate transfer drum 53 as the photosensitive drum 51 rotates.

The intermediate transfer drum 53 is rotated at the same peripheral speed as the photosensitive drum 51 in the direction of the arrow (counterclockwise) in the figure by a driving means (not shown). Is intermediately transferred to the peripheral surface.
Then, it moves to the secondary transfer nip with the rotation of the intermediate transfer drum 53.

On the other hand, a paper feeding device (not shown)
Is sent out toward the transfer nip at such a timing that it can be superimposed on the visible image. The transfer paper 56 superimposed on the visible image at the transfer nip is sent from the secondary transfer nip to a fixing device (not shown) after the visible image is transferred from the intermediate transfer drum 53. Then, the visible image is fixed here by heating or the like, and then discharged outside the printer.

The untransferred developer remaining on the photosensitive drum 51 without being transferred to the intermediate transfer drum 53 is mechanically scraped and removed by a cleaning blade 54a of the drum cleaning unit 54. And it is conveyed to the collection pipe 58 by the screw member 54b, falls in this collection pipe 58 by its own weight, and reaches the second tank described later.

After the liquid developer remaining on the surface of the intermediate transfer drum 53 that has passed through the secondary transfer nip is not transferred to the transfer paper 56 and is removed by an intermediate transfer drum cleaning unit (not shown), the photosensitive drum 51 is removed. Move to the contact position again.

The photosensitive drum 51 having passed this contact position
The front surface is moved to a position facing an unillustrated static elimination lamp to remove the residual potential, thereby preparing for the next print.

The developing unit 100 includes a developing unit 101
And a collection unit 102 as a collection unit, and an agent adjustment unit 103.

The developing unit 101 includes a developing roller 105 as a developer carrier, an application roller 106, a regulating blade 107, a first stirring screw 108, a second stirring screw 109, a first tank 110, and the like. In the first tank 110, a liquid developer 57 containing a toner, which is a developing substance, and a liquid carrier is filled with 100 to 150 liquid developer.
It is housed in the amount of [cc].

The liquid developer 57 has a viscosity of 100 to 1
0000 [mPa · s] and the toner density is 5
It is adjusted to ~ 40 [%]. More specifically, in the present embodiment, the viscosity = about 300 [mPa · s] and the toner concentration =
15% is used.

In the first tank 110, the coating roller 106 is disposed above the liquid developer 57,
In the standby state, the liquid level of the liquid developer 57 is
To avoid contact with Further, the first stirring screw 108 and the second stirring screw 109 are horizontally disposed so as to be arranged in parallel with each other.

When the printing operation is started, these screws are rotated in opposite directions by driving means (not shown), and the liquid developer 57 above the screws rises the liquid surface and comes into contact with the application roller 106 to be supplied. Is done. The liquid developer 57 thus supplied
When passing through the position facing the regulating blade 107 together with the application roller 106 which is rotated counterclockwise in the figure by a driving means (not shown), the layer thickness is regulated and thinned. And a part of the coating roller 10
After being applied at a rate of about 30 [cc] per minute to the developing roller 105 rotating while contacting with the developing roller 6, the developing roller 105 moves together with the developing roller 105 to a developing position which is a position facing the photosensitive drum 51 and contributes to development. I do. At this developing position, the developing roller 1 is moved without moving to the electrostatic latent image on the photosensitive drum 51.
The undeveloped developer remaining on the surface 05 moves to a position facing the collecting section 102 with the rotation of the developing roller 105 and is collected.

The collecting section 102 includes a collecting roller 111,
A collecting blade 112, a collecting screw 113, and a collecting pipe 114 are provided. The collecting roller 111 rotates while contacting the surface of the developing roller 105 after passing through the developing position, and collects the undeveloped developer adhered to the surface. The undeveloped developer thus collected is collected by the collecting blade 112 by the collecting roller 112.
After being mechanically scraped and removed from the surface of the collecting pipe 113, it is conveyed into the collecting pipe 114 by the collecting screw 113. Then, the collection pipe 114 falls by its own weight and reaches a second tank described later.

The agent adjusting unit 103 includes a second tank 115 as an agent storing unit, two wing members 116 and 117, a concentration signal output unit 118, a transport pump 120, and a transport pipe 1.
21 and the like. The second tank 115 also contains the liquid developer 57 therein, and the tank lid 119 is attached to the opening thereof.

The density signal output means 118 constitutes a density detection means together with a control unit which is a control means (not shown).

In the second tank 115, the wing members 116 and 117 are rotated by a stirring motor (not shown) to rotate the liquid developer 57 in a substantially horizontal direction to stir. The toner density of the liquid developer 57 is detected by the density detection means including the density signal output means 118 and the control unit while being stirred in this manner.

One end of the transfer pipe 121 has a second shape.
The other end is connected to the drain pipe 122 of the first tank. The transfer pump 120 is provided in the middle of the transfer pipe 121. The liquid developer 57 in the second tank 115 is transported and supplied into the first tank 115 by the transport pump 120. First tank 1 by transfer pump 120
When an excessive amount of the liquid developer 57 is supplied to the inside of the tank 15, the surplus liquid developer reaches a mounting position of an overflow pipe (not shown) due to a rise in the liquid level of the liquid developer 57 in the first tank 115. It returns to the second tank 115 through this overflow pipe.

The liquid supply device 1 includes an agent storage section 2 for storing a supply developer, a carrier storage section 3 for storing a supply liquid carrier, and a second tank 115 from the storage section.
And a supply pump 4 for transporting the liquid to the apparatus, and is controlled by a control unit (not shown).

The supply developer in the developer container 2 has a toner concentration of the liquid developer 57 in the second tank 115.
Is higher than.

The control section controls the driving of the supply pump 4 and the like based on the output signal from the concentration signal output means 118 of the agent adjusting section 103 to store an appropriate amount of the liquid carrier in the second tank 115. By supplying the supply developer, the toner concentration of the liquid developer 57 in the second tank 115 is adjusted. By such control, the developing roller 1
The toner concentration of the mixture of the undeveloped developer recovered from the photoreceptor 05 and the untransferred developer recovered from the photosensitive drum 1 is different from the toner concentration of the liquid developer 57 before being used for development. Even in such a case, it can be returned to the second tank 115 and reused.

Next, a characteristic configuration of the printer according to the embodiment will be described. FIG. 5 is an enlarged configuration diagram showing the supply device 1. In the figure, one port of a supply pump 4 of a supply device 1 has a first port F1 through a first flow path F1.
A first electric three-way valve 11 as a switching means is connected. The first electric three-way valve 11 is configured such that the state in which the first flow path F1 and the second flow path F2 are connected so that liquid can flow through the first flow path F1 and the third flow path F3 is controlled by drive control by a control unit (not shown). Channel F
3 can be switched to a state where it is connected so that the liquid can flow. The second flow path F2 having one end connected to the first electric three-way valve 11 has the other end connected to the agent container 2 via a connector. In addition, the third flow path F3, one end of which is connected to the first electric three-way valve 11, has the other end extending toward the second tank 135, which is an agent reservoir.

In the other port of the supply pump 4,
A second electric three-way valve 21 as a second switching means is connected via the fourth flow path F4. This second electric three-way valve 21
Is a state in which the fourth flow path F4 and the fifth flow path F5 are connected so that the liquid can flow through the drive control by the control unit, and the liquid flow can be performed between the fourth flow path F4 and the sixth flow path F6. Can be switched to the connected state. The second electric three-way valve 21
Is connected to the carrier 3 via a connector at the other end. The sixth flow path F6, one end of which is connected to the electric three-way valve 21, has the other end extending toward the second tank 135.

The supply pump 4 includes a first flow path F1 and a fourth flow path F1.
A pump unit 4b for applying a propulsive force to the liquid in the flow path F4, and a motor 4a serving as a drive source of the pump unit are provided, and the liquid in the first flow path F1 and the fourth flow path F4 is conveyed in a fixed amount. Has become possible. ing. When the motor 4a is rotated forward by the control unit, the pump unit 4b
The liquid in 1 is sucked and discharged to the fourth flow path F4. Also,
When the motor 4a is rotated in the reverse direction, the pump unit 4b draws the liquid in the fourth flow path F4 and turns the first flow path F1.
To be discharged. The supply pump 4 includes a pump unit 4 including a gear pump mechanism, a tube pump mechanism, and the like.
b is rotated by a motor 4a such as a stepping motor.

When the supply developer in the developer container 2 is supplied to the second dunk 135, as shown in FIG. 6, the second electric three-way valve 21 connects the fourth flow path F4 to the sixth flow path F4. After the drive is controlled so that the liquid flows through the path F6, the motor 4a of the supply pump 4 is driven to rotate forward. On the other hand, the drive of the first electric three-way valve 11 is controlled such that the liquid flows through the first flow path F1 and the second flow path F2. With such control,
The supply developer in the agent container 2 is supplied to the second dunk 135 through an agent transport path of the second channel F2 → the first channel F1, the fourth channel F4 → the sixth channel F6.

On the other hand, when the liquid carrier in the carrier agent storage section 3 is supplied to the second dunk 135, as shown in FIG. 7, the second electric three-way valve 21 is connected to the fourth flow path F4 and the fifth flow path F4.
After the drive is controlled so that the liquid flows through the flow path F5, the motor 4a of the supply pump 4 is driven to rotate in the reverse direction. On the other hand, the drive of the first electric three-way valve 11 is controlled so that the liquid flows through the first flow path F1 and the third flow path F3. By such control, the liquid carrier in the carrier storage unit 3
The second dunk 135 is provided by the carrier transport path of the fifth flow path F5 → the fourth flow path F4, the first flow path F1 → the third flow path F3.
Supplied to

In the liquid supply by such a liquid supply device 1, the sixth flow path F6 is used as a discharge flow path downstream of the supply pump 4, but only the supply developer flows here. . The third flow path F3 is also used as a discharge flow path downstream of the supply pump 4, but only the liquid carrier flows here. Therefore, no matter how long the sixth flow path F6 or the third flow path F3, which is the discharge flow path, becomes long, the residual liquid in the sixth flow path F6 may adversely affect the concentration adjustment of the liquid developer in the agent storage unit 200. There is no.

In such a configuration, when the supply of the liquid carrier is started from the state where the agent transport path is secured, first, the driving of the second electric three-way valve 21 and the supply pump 4
And start the reverse rotation drive, with a slight time lag,
It is desirable to start driving the first electric three-way valve 11.

Specifically, as shown in FIG. 8, first, the drive of the second electric three-way valve 21 is started, and
→ Fifth flow path F5 → Fourth flow path F4 → First flow path F1 → Second flow path → Supply pump 4 while securing a transport path between carrier storage unit 3 and agent storage unit 2 called agent storage unit 2. Is driven in reverse. Then, the supply developer that has been present in the first flow path F1 is changed to the second flow path F2 or the agent storage portion 2 ahead of the second flow path F2.
, The liquid carrier is sent from the fifth flow path F5 into the fourth flow path F4. Then, when the first electric three-way valve 11 is driven with a slight time lag, as shown in FIG. 9, a carrier transport path is secured and the supply of the carrier to the second tank 135 is started. With such a configuration, it is possible to prevent the supply developer from being mixed from the first flow path F1 to the third flow path F3. However, the supply developer initially present on the fifth flow path F5 side in the fourth flow path F4 is conveyed toward the first flow path F1 while being mixed little by little with the liquid carrier to reduce the concentration. Thinning. Therefore, it is more desirable that the driving of the first electric three-way valve 11 be started at such a timing that this is not returned into the second flow path 2.

Although an example has been described in which the first electric three-way valve 11 and the second electric three-way valve 21 are driven by different motors, the distance between the common flow path (F1 + F4) is made sufficiently short so that both valves are driven. If there is no problem even if the driving starts at the same time, both valves can be driven by one motor as shown in FIG. In the illustrated example, each time the motor shaft is repeatedly rotated forward and backward by 90 [°], the state in which the agent transport path is secured and the state in which the carrier transport path is secured can be obtained alternately.

When the distance of the common flow path is sufficiently short, the first switching section 12 and the first switching section 12 as shown in FIG. The two-switching unit 22 can be used. In the figure, a first switching unit 1
Reference numeral 2 denotes a branch portion that branches the first flow path F1 into two, an upstream check valve 12a that blocks liquid flow from the branch portion to the second flow path F2, and a branch portion that extends from the third flow path F3. And a downstream non-return valve 12b for preventing the flow of the liquid to the downstream side. The second switching section 22 includes a branch section that branches the fourth flow path F4 into two, an upstream check valve 22a that blocks liquid flow from the branch section to the fifth flow path F5, and a sixth switch section. A downstream check valve 22b for preventing liquid flow from the flow path F6 to the branch portion.

When the motor 4a of the supply pump 4 is rotated forward, as shown in FIG. 12, the liquid in the first flow path F1 is sucked into the pump section 4b, and the propulsion force directed to the fourth flow path F4 side. Is given. With this propulsion, the first flow path F1
The liquid inside tries to draw in the liquid in the second flow path F2 and the third flow path F3. Since the upstream check valve 12a of the first switching section 12 allows the liquid flow from the second flow path F2 to the branch section, the developer supplied in the second flow path F2 is not supplied to the first flow path F1. It is drawn into the branch by the liquid flow. However, the first switching unit 1
Since the second downstream check valve 12b prevents the liquid flow from the third flow path F3 to the branch, the liquid carrier from the third flow path F3 to the branch due to the liquid flow in the first flow path F1 Backflow is prevented.

When the liquid is discharged from the pump section 4b of the supply pump 4, the liquid in the fourth flow path F4 is switched to the second switching section 22b.
Propulsion toward is provided. With this driving force, the fourth
The liquid in the flow path F4 tries to enter the fifth flow path or the sixth flow path via the branch portion of the second switching unit 22. Second switching unit 22
The upstream check valve 22a of the second switching section 22 allows the downstream check valve 22b to allow the liquid flow from the branch portion to the sixth flow path F6, so that the liquid in the fourth flow path F4 It enters the sixth flow path F6 via the branch portion and is supplied to the second tank 135. However, the upstream check valve 22a of the second switching unit 22
Prevents the liquid flow from the branch portion to the fifth flow path F5,
Backflow from the branch portion to the fifth flow path F5 due to the liquid flow in the fourth flow path F4 is prevented.

Such upstream check valves 12a, 22a,
When the motor 4a of the supply pump is rotated forward by the action of the downstream check valves 12b and 22b, the agent container 2 → second
Flow path F2 → first flow path F1 → fourth flow path F4 → sixth flow path F6
Is automatically secured.

On the other hand, when the motor 4a of the supply pump 4 is reversed, as shown in FIG.
Carrier storage part 3 → fifth flow path F5 → fourth flow path F4 → first
The carrier transport path from the flow path F1 to the third flow path F3 is automatically secured.

Therefore, when the first switching unit 12 and the second switching unit 22 are used as the first switching unit and the second switching unit, a special driving source is not connected to the first switching unit and the second switching unit. Switching to the carrier transport path can be performed.

As shown in FIG. 14, the upstream check valves 12a and 22a are arranged such that a check ball is formed by a spring toward a communication port between the branch and the second flow path F2 or the fifth flow path. One that is urged from the side or one that is dropped from the second flow path F2 or the fifth flow path by gravity as shown in FIG. Further, as shown in FIG. 14, the downstream check valves 12b and 22b urge the check balls from the third flow path or the sixth flow path toward the communication port, as shown in FIG. As shown in (1), the one dropped by the gravity from the branch portion side toward the communication port can be considered.

Next, a description will be given of an embodiment apparatus in which a more characteristic configuration is added to such a printer. FIG.
FIG. 2 is an enlarged configuration diagram illustrating a liquid supply device 1 of the printer according to the embodiment. In the figure, a check valve 30 is provided in a fifth flow path F5 of the liquid supply device 1 so as to maintain a predetermined distance from the second switching unit 22. This check valve 30 has a second
During the operation of the upstream check valve 22a of the switching unit 22, after flowing backward from the branch into the fifth flow path F5, the branch and the check valve 22a
Convection in the vicinity of the communication port, and also stops in the fifth flow path F5 due to the stop of the carrier supply, and plays a role of suppressing the backflow of the toner into the carrier accommodating section 3. Therefore,
Carrier contamination due to the backflow toner can be suppressed.

Near the middle point of the fourth flow path F4, a third electric three-way valve 40 as a third switching means is provided. The third electric three-way valve 40 is connected to the fourth flow path portion F4a on the supply pump 4 side and the second
A state in which the fourth flow path portion F4b on the switching section 22 side is connected so that the liquid can flow therethrough is referred to as a fourth flow path portion F4a on the supply pump 4 side.
And the seventh flow path F7 can be switched to a state where they are connected so that liquid can flow. The seventh flow path F7, one end of which is connected to the third electric three-way valve 40, has the other end connected to the agent container 2 via a connector. The second flow path F2 is
It is connected to the agent container 2 so as to include this connection.

In a state where the third electric three-way valve 40 connects the fourth flow path portion F4a on the pump side and the fourth flow path portion F4b on the switching section so that the liquid can flow, the motor 4a of the supply pump 4 is operated normally. When the roller is driven to rotate, as shown in FIG.
The supply developer is supplied to 35.

On the other hand, in a state where the third electric three-way valve 40 connects the fourth flow path portion F4a on the pump side and the seventh flow path F7 so that the liquid can flow, the motor 4a of the supply pump 4 is driven to rotate forward. Then, as shown in FIG. 18, the agent container 2 →
A return transport path of the second flow path F2 → the first flow path F1 → the fourth flow path portion F4a on the pump side → the seventh flow path F7 is secured. As a result, the supply developer transported from the agent storage unit 2 returns to the agent storage unit 2 again via the return transport path, and rises to the supply developer existing substantially at the center in the horizontal direction in the agent storage unit. Give propulsion. As a result, in the agent container 2, the supply developer rises at a position substantially at the center in the horizontal direction, reaches near the liquid surface, diffuses radially, and then descends to the second flow path F2 having a large diameter. A liquid stream is created that is sucked.
Then, the toner is satisfactorily dispersed in the supply developer by the liquid flow, and the toner concentration of the supply developer becomes uniform.

The liquid flow in the agent container 2 becomes more active as the liquid flow speed from the seventh flow path F7 increases, and the toner is dispersed well. Therefore, when the supply developer is stirred by the return transport path, the rotation speed of the motor 4a of the supply pump 4 may be higher than when the developer is supplied to the second tank 135.

In the return conveyance path, as shown in FIG. 19, the supply developer may be returned not from the fourth flow path F4 but from the sixth flow path F6. In this case, it is possible to eliminate carrier mixing from the inside of the fourth flow path F4, which is the common flow path, to the seventh flow path F7. Also,
Since the third electric three-way valve 40 does not need to be disposed in the fourth flow path F4, the common flow paths (F1, F
4) Longer distance can be eliminated.

The printer that forms a single-color image using one developing unit 100 has been described above.
(Yellow), M (magenta), C (cyan), and K (black) liquid developers for storing Y developer, M developer,
The present invention is also applicable to an image forming apparatus that forms a full-color image using a C developing device and a K developing device. In such an image forming apparatus, four liquid supply devices for Y, M, C, and K are required.
As shown in FIG. 0, it is possible to provide only one carrier accommodating section 3 and share them. Even if shared in this manner, the check valves 30Y, 3Y
If 0M, 30C, and 30K are provided, it is possible to suppress the backflow of the toner of each color into the carrier storage unit 3. Thus, it is possible to suppress color mixing of the respective color developers via the liquid carrier.

[0065]

According to the first, second, third, fourth, fifth, sixth or seventh aspect of the present invention, the supply developer and the liquid carrier are individually supplied by one supply pump, respectively. There is an excellent effect that it is possible to eliminate the cost increase and the increase in the size of the apparatus, in which one supply pump is provided.
In addition, no matter how long the discharge flow path is, the residual liquid in the discharge flow path does not adversely affect the concentration adjustment of the liquid developer in the developer storing section. There is an excellent effect that the difficulty in adjusting the concentration of the liquid developer due to the residual liquid can be solved.

In particular, according to the invention of claim 2, the supply developer in the common flow path is mixed with the liquid carrier in the third flow path, or the liquid carrier in the common flow path is mixed in the sixth flow path. This has an excellent effect of suppressing the situation of mixing in the supply developer and reducing the adverse effect on the density adjustment caused by such mixing.

In particular, according to the third aspect of the present invention, the first
There is an excellent effect that the flow path can be switched without connecting a special driving means to the switching means or the second switching means.

In particular, according to the fourth aspect of the present invention, even if the concentration of the supply developer is not uniform due to the sedimentation of the developing substance in the developer container, the developer can be made uniform by stirring. In addition, there is an excellent effect that it is possible to suppress the difficulty in adjusting the concentration of the liquid developer due to the non-uniform density.

In particular, according to the fifth or sixth aspect of the invention, carrier contamination due to the backflow of the developing substance in the fifth flow path can be suppressed. Further, by suppressing such carrier contamination, when a single carrier accommodating portion is connected to and shared by a plurality of supply pumps for transporting supply developers of different colors for multicolor image formation, the liquid There is an excellent effect that color mixture of the liquid developer via the carrier can be suppressed.

In particular, according to the invention of claim 6, the fifth aspect
There is an excellent effect that carrier contamination due to the backflow of the developing substance in the flow path can be suppressed more reliably.
Furthermore, when one carrier accommodating portion is connected to and shared by a plurality of supply pumps for respectively supplying supply developers of different colors, color mixing of the liquid developer via the liquid carrier can be more reliably performed. There is an excellent effect that it can be suppressed.

In particular, according to the invention of claim 7, there is an excellent effect that the density of the liquid developer can be satisfactorily adjusted to stabilize the image density.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a developer transport path of a liquid supply device according to the present invention.

FIG. 2 is a schematic diagram illustrating a carrier transport path of the liquid supply device.

FIG. 3 is a schematic diagram illustrating a drive time lag of a first switching unit of the liquid supply device.

FIG. 4 is a schematic configuration diagram illustrating a printer according to the embodiment.

FIG. 5 is an enlarged configuration diagram showing a liquid supply device of the printer.

FIG. 6 is an enlarged configuration diagram showing the liquid supply device in a state in which the agent transport path is secured.

FIG. 7 is an enlarged configuration diagram showing the liquid supply device in a state where a carrier transport path is secured.

FIG. 8 is an enlarged configuration diagram showing the liquid supply device in a state where the drive start of the first electric three-way valve is delayed.

FIG. 9 is an enlarged configuration diagram showing the liquid supply device in which the driving of the first electric three-way valve is started.

FIG. 10 is a perspective view showing an example of the liquid supply device.

FIG. 11 is an enlarged configuration diagram illustrating a modified example device according to the supply device.

FIG. 12 is an enlarged configuration diagram showing the device of the modified example in a state where the agent transport path is secured.

FIG. 13 is an enlarged configuration diagram showing the same modified example device in a state where a carrier transport path is secured.

FIG. 14 is an enlarged sectional view showing an example of a first switching unit or a second switching unit of the modification.

FIG. 15 is an enlarged sectional view showing another example of the first switching unit or the second switching unit.

FIG. 16 is an enlarged configuration diagram illustrating a liquid supply device of the printer according to the embodiment.

FIG. 17 is an enlarged configuration diagram showing the liquid supply device in a state in which the agent transport path is secured.

FIG. 18 is an enlarged configuration diagram showing the liquid supply device in a state where a return transport path is secured.

FIG. 19 is an enlarged configuration diagram illustrating a modified example device according to the liquid supply device.

FIG. 20 is a schematic configuration diagram showing another modified example of the liquid supply device.

FIG. 21 is a schematic diagram illustrating an example of a liquid supply device that supplies a supply developer and a liquid carrier using a single supply pump.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 liquid supply device 2 agent storage section 3 carrier storage section 4 supply pump 4 a motor 4 b pump section 10 first switching means 11 first electric three-way valve (first switching means) 11 a motor 12 first switching section (first switching means) 12a upstream check valve 12b downstream check valve 20 second switching means 21 second electric three-way valve (second switching means) 21a motor 22 second switching unit (second switching means) 22a upstream check valve 22b downstream Side check valve 30 Check valve 40 Third electric three-way valve (third switching means) 51 Photoconductor drum (latent image carrier) 100 Developing unit (developing device) 135 Second tank (agent reservoir)

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 2H074 AA03 BB02 BB08 BB32 CC22 CC26 CC32

Claims (7)

[Claims] An agent container for accommodating a supply developer containing a developing substance and a liquid carrier; a carrier container for accommodating a liquid carrier; and developing the supply developer and the liquid carrier in the carrier container. A first flow path connected to one port of the supply pump, and a second flow path branched from the one port to reach the agent storage section, the liquid supply apparatus including a supply pump for supplying the agent to the agent storage section of the apparatus. A third flow path branched from the first flow path to reach the agent storing section, a first switching means for switching liquid flow with the first flow path between the second flow path and the third flow path,
A fourth flow path connected to the other port of the supply pump, a fifth flow path branched from the fourth flow path to the carrier accommodating portion,
A sixth flow path that branches from the flow path to the agent storage section, a second switching unit that switches liquid flow through the fourth flow path between the fifth flow path and the sixth flow path, and the supply A liquid supply device comprising a transfer direction switching means for switching a liquid transfer direction by a pump. 2. The liquid supply device according to claim 1, wherein
A liquid supply apparatus characterized in that the switching of the flow path by the switching means or the second switching means is delayed from the start of driving of the supply pump. 3. The liquid supply device according to claim 1, wherein the first
A check valve that stops backflow in the second flow path or the fifth flow path, and a check valve that stops backflow in the third flow path or the sixth flow path, as the switching means or the second switching means. A liquid supply device characterized by using a liquid supply device. 4. The liquid supply apparatus according to claim 1, wherein a seventh flow path toward the agent storage section is connected to the fourth flow path or the sixth flow path, and the supply position is higher than a connection position. The flow of liquid with the fourth flow path portion on the pump side is switched between the fourth flow path portion and the seventh flow path on the second switching means side, or the second switching means side from the connection position A liquid supply device provided with a third switching means for switching the liquid flow through the sixth flow path part between the sixth flow path part on the agent storage part side and the seventh flow path. 5. The liquid supply device according to claim 1, wherein a check valve is provided in a portion of the fifth flow path at a predetermined distance from the second switching means. Liquid supply device. 6. The liquid supply apparatus according to claim 5, wherein the supply amount of the liquid carrier per carrier conveyance by the supply pump is determined by a difference between the second switching means and the check valve in the fifth flow path. A liquid supply device characterized in that the liquid supply amount is larger than the intervening liquid amount. 7. A latent image carrier for carrying a latent image, a latent image forming means for forming a latent image on the latent image carrier, and a latent image using a liquid developer containing a developing substance and a liquid carrier. 2. An image forming apparatus comprising: a developing device for developing a latent image on a carrier; and a liquid supply device for supplying a liquid developer and a liquid carrier to a developer reservoir of the developing device, wherein the liquid supply device is used as the liquid supply device. An image forming apparatus comprising: 2, 3, 4, 5, or 6;