JP2000194197A - Electrophotographic device and liquid developer supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic device which is easily made compact, whose structure is simplified and which is constituted so that an image can be stably formed by reducing the exposing of liquid developer to the air and uniformizing and stabilizing the supplying speed of the liquid developer to a developing part regardless of the diameter of a developing roller. SOLUTION: This electrophotographic device is provided with a latent image forming means forming a latent image on a latent image holding body 1 and a developing means visualizing the latent image by supplying the liquid developer to it. The developing means is provided with a developer carrier carrying the liquid developer and a means supplying the liquid developer to the developer carrier. Then, the means supplying the liquid developer is arranged near the holding body 1 by being opposed to it and provided with a primary liquid developer storage part 11 whose width is almost equal to or wider than that of the latent image forming surface of the holding body 1 and a guide path guiding the liquid developer overflowing at the part of the storage part 11 on the holding body 1 side to the developer carrier.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus using a liquid developer and a liquid developer supply device used in the electrophotographic apparatus.

[0002]

2. Description of the Related Art A wet electrophotographic apparatus using a liquid developer has an advantage which cannot be realized by a dry electrophotographic apparatus, and therefore, its value has recently been reviewed. The advantages of a wet electrophotographic apparatus over a dry electrophotographic apparatus are that it is possible to use a very fine toner having a submicron size to achieve high image quality, and it is economical because a sufficient amount of image can be obtained with a small amount of toner. (E.g., offset printing), and that the toner can be fixed on paper at a relatively low temperature to save energy.

On the other hand, the conventional wet electrophotographic technique using a liquid toner has some problems. One of the problems is that a liquid developer using a high-resistance or insulating petroleum-based solvent as a carrier solvent must be used to develop an electrostatic latent image.

That is, since a liquid developer is used, it is necessary to sufficiently bring the developer into close contact with the surface of the photosensitive layer in the developing section, which requires a mechanism for positively supplying the developer using a pump or the like. At this time, if the supply speed of the developer is too slow, the amount of toner carried to the image forming portion of the photosensitive layer becomes insufficient, so that the coloring or insufficient contrast occurs.If the supply speed is too fast, the excess toner is supplied. This causes a problem that the image density becomes too high. Further, if the supply speed is uneven, the unevenness in the density of the image is a cause of the unevenness, and a great inconsistency is caused in the formation of a high quality image which is the greatest advantage of the wet electrophotographic system.

FIGS. 8 and 9 show examples of the structure of a developing device of a conventional wet electrophotographic apparatus. Many of the developing mechanisms of a conventional wet electrophotographic apparatus have a configuration in which a developing roller 30 is rotated, a liquid developer is adhered to the surface of the developing roller 30, and is conveyed to a developing section of a photosensitive drum 31, as shown in FIGS. Has been taken. That is, the lower portion of the developing roller 30 is immersed in the liquid developer pool stored in the container. When the developing roller 30 rotates, the liquid developer adheres to the surface of the developing roller 30 and is transported accordingly. Then, the liquid developer is carried to the very small gap between the developing roller 30 and the photosensitive drum 31,
Perform development.

In the developing device having such a configuration, the transport speed of the liquid developer depends on the affinity between the surface of the developing roller 30 and the liquid developer, the rotational speed of the developing roller 30, the developing roller 30 and the liquid developer reservoir. , That is, the developing roller 3
It is determined by the height of the liquid developer surface with respect to 0 or the like. Therefore, a control mechanism that keeps the liquid level at a predetermined position is required.

In the developing device shown in FIG. 8, the liquid developer is
The liquid developer is supplied from the bottom of the liquid developer reservoir to the liquid developer reservoir by a circulation pump or the like. In the developing device shown in FIG. 9, the liquid developer flows down from a nozzle above the liquid level of the liquid developer, and Although supplied to the developer pool, if the liquid surface sometimes undulates during development due to pulsation of the pump or impact when flowing down, the contact width between the developing roller 30 and the liquid developer changes, and the Affects concentration.

There is another disadvantage of the system in which the developing roller 30 is immersed in the liquid developer pool. For example, if an extremely small-diameter roller is used for the developing roller 30, the effect of the height error of the liquid level on the adhesion amount on the surface of the development roller 30 becomes extremely large, and the above-described adhesion amount control becomes difficult to stabilize. Stable supply of the developer becomes extremely difficult. Another problem is that a relatively large amount of liquid developer must always be stored in a container.

As described above, the liquid developer is obtained by dispersing a toner in a petroleum-based solvent. This solvent evaporates relatively easily, and if it leaks out of the machine, odors and allergic effects on the human body pose problems. For this reason, in a wet developing mechanism, the liquid developer is supplied only on the photosensitive drum during development so that the exposure time of the liquid developer to the air is minimized, and collected in a tank when unnecessary. It is also necessary to devise ways to store and minimize the generation of solvent vapors.

However, in the above-described developing mechanism, a relatively large amount of liquid developer must always be stocked at the time of development, and since the liquid developer is exposed to air during the developing operation, the solvent is relatively small. Evaporates easily. In particular, when the diameter of the developing roller 30 is to be increased, the opening area of the liquid developer becomes extremely large, and the solvent is more easily evaporated.

Therefore, another type of liquid developer supply device (US Pat. No. 5,585,900) will be described which is different from the type in which the roller is immersed in the liquid developer pool. In this type of liquid developer supply device, there is one developing roller for four colors of liquid developer, and transfer is performed for each color. The supply of the liquid developer to the developing roller is performed directly on the surface of the developing roller by jetting from a plurality of nozzles arranged in the width direction of the developing roller. The ejected liquid developer is leveled by a blade or a roller with the rotation of the developing roller, and then carried on the photosensitive drum to be developed.

In this method, it is easy to control the amount of the liquid developer carried in one development, and uneven development density due to the uneven amount of the liquid developer hardly occurs. Further, since the required amount of the liquid developer is ejected during the developing operation, there is an advantage that unlike the conventional examples shown in FIGS. 8 and 9, the generation of the solvent vapor from the liquid pool is small.

However, in this configuration, a liquid developer supply mechanism for uniformly ejecting the developer in the width direction of the developing roller is required, and the pipe for that purpose occupies an extremely large volume. In particular, since a mechanism for supplying the liquid developer from the front side of the developing roller is provided, in a structure in which a plurality of developing mechanisms are arranged in parallel, the distance between the developing mechanisms must be increased. Also, when trying to make the pipe itself smaller, the pipe diameter becomes thinner, which easily causes clogging, and as a result,
It is impossible to realize a small device with this mechanism.

FIG. 10 shows a conventional example of still another structure. In the example shown in FIG. 10, an elastic blade 33 is uniformly pressed in the width direction on the developing roller 30 or is arranged in a state of being close to the blade 33. This blade and the developing roller 30
The liquid developer is continuously supplied from the side surface or the front surface of the cylindrical shaft of the developing roller 30 to the pseudo-triangular gap formed by the formula (1) to form a temporary liquid pool. The amount of the liquid developer in the liquid pool is balanced when the amount leaked from each gap and the supplied amount are balanced. When the developing roller 30 rotates, the liquid developer is scooped up from the liquid pool and supplied to the photosensitive drum surface. . The supply of the liquid developer to the gap formed by the blade 33 is performed simultaneously with the start of the development, and is stopped when the development is completed.

This method has a problem that it is difficult to reduce the size when supplying the liquid developer from the front of the developing roller 30 as in the above-described example. Developing roller 30
In the case of supplying from the side surface in the axial direction, the size can be reduced, but there is a problem that the image at the end near the supply position becomes relatively dark. This is because when the liquid developer is supplied from the side, before the liquid developer flows uniformly in the width direction,
This is because the developer is further scooped up from the surface of the developing roller 30 at a position closer to the supply position, and as a result, the supply amount of the liquid developer increases at the end closer to the supply position.

Therefore, the liquid developer cannot be fed onto the photosensitive drum in a uniform amount in the width direction. Further, when the liquid developer undulates due to pulsation of a pump or the like, unevenness in the density of development also occurs.

[0017]

As described above, in the conventional electrophotographic apparatus, both miniaturization of the apparatus and stable supply of the liquid developer to the photosensitive drum are achieved, and uniform development of the liquid developer is achieved. It was difficult to supply to the department.

In view of such circumstances, the present invention is easy to miniaturize, has a simple structure, and has little exposure of the liquid developer to air irrespective of the diameter of the developing roller. An object of the present invention is to provide an electrophotographic apparatus capable of uniformly and stably supplying the liquid developer at a constant speed, thereby enabling stable image formation.

Another object of the present invention is to provide a liquid developer supply device for such an electrophotographic apparatus.

[0020]

In order to solve the above-mentioned problems, the present invention provides a latent image forming means for forming a latent image on a latent image holding member, and a method for supplying a liquid developer to the latent image to make the latent image visible. An electrophotographic apparatus having a developing unit for forming an image, wherein the developing unit includes a developer carrier for carrying the liquid developer, and a unit for supplying the liquid developer to the developer carrier. The means for supplying a liquid developer is disposed opposite to the vicinity of the latent image holding member, and has a width substantially equal to or wider than the width of the latent image forming surface of the latent image holding member. And a guide path for guiding the liquid developer overflowing on the side of the latent image holding member of the liquid developer primary storage section to the developer carrier. I do.

According to the present invention, there is provided a latent image forming means for forming an electrostatic latent image on a latent image holding member, and a liquid developer for supplying a liquid developer to the electrostatic latent image to visualize the electrostatic latent image. A liquid developer supply device for an electrophotographic apparatus, comprising: a developing unit having a developer carrying member for carrying a developer; A liquid developer primary storage portion having a width substantially equal to or larger than the width of the image forming surface; and the developer carrying the liquid developer overflowing on the latent image holding member side of the liquid developer primary storage portion. A liquid developer supply device, comprising: a guide path leading to a body.

According to the electrophotographic apparatus and the liquid developer supply apparatus of the present invention configured as described above, a necessary and sufficient amount of the liquid developer is stably supplied to the developing section at the time of electrophotographic development in which liquid development is performed. And thereby stabilize the image.

In the electrophotographic apparatus and the liquid developer supply apparatus according to the present invention, the following aspects are further possible.

(1) The liquid level of the liquid developer in the liquid developer primary storage section is higher in the direction of gravity than the portion on the developer carrier to which the liquid developer is supplied.

(2) One end of the guide path for guiding the liquid developer to the developer carrying member is attached to the latent image holding member of the liquid developer primary storage section, and the other end contacts or contacts the latent image holding member. Being a plate-like member arranged in the vicinity.

(3) The liquid developer primary storage section has a liquid developer introduction port on the side or bottom surface and a liquid developer collection port on the bottom surface, and prints the liquid liquid developer from the liquid developer introduction port. The liquid developer is collected at the start, and the liquid developer is collected from the liquid developer collection port when the printing operation is stopped. (4) The liquid developer overflows from the primary storage portion of the liquid developer, passes through the guide path, and carries the developer. And a means for detecting the level of the liquid level of the developer carrier that has flowed into the liquid developer reservoir surrounded by the body, and controls the supply speed of the liquid developer supplied to the liquid developer primary storage unit. By doing so, the height of the liquid level of the liquid developer reservoir is maintained constant, thereby maintaining a predetermined image density.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below, and the present invention will be described more specifically and in detail.

FIG. 1 shows an image forming section of an electrophotographic apparatus according to one embodiment of the present invention. In the electrophotographic apparatus shown in FIG. 1, the latent image carrier 1 is a photosensitive drum having a structure in which an organic or amorphous silicon photosensitive layer is provided on a conductive substrate. After the photosensitive layer surface is uniformly charged by a well-known first corona charger or scorotron charger 2a, the latent image holder 1 receives a first exposure 3a by an image-modulated laser beam. ,
An electrostatic latent image is formed on the surface of the photosensitive layer. Thereafter, the electrostatic latent image is visualized by the first developing device 4a that stores the liquid developer.

The liquid developer or toner particles attached to the electrostatic latent image may be directly transferred to a transfer step and transferred to a sheet by a transfer device.
A second electrostatic latent image is formed by the charging device 2a and the second laser exposure 3a, and a second developer of a different color from the liquid developer stored in the first developing device 4a is stored. The image is developed by the second developing device 4b. Therefore, after the second development, two color toner images are formed on the latent image holding member 1.

Similarly, third and fourth developments are performed.
A full-color toner image is formed on the latent image holding member 1.
This toner image is transferred to a sheet by a transfer device. In this case, the toner image may be directly transferred to the sheet, or may be transferred to the sheet 9 via the intermediate transfer medium 6 as illustrated in FIG. good. In the transfer from the latent image holding member 1 to the intermediate transfer medium 6 and the transfer from the intermediate transfer medium 6 to the paper 9, either transfer by electric field or transfer by pressure (and heat) can be used. . The liquid developer is
Generally, there are many types that can be fixed on paper at room temperature, but fixing may be performed by heating the intermediate transfer medium 6 or the like.
Such an image forming process is described, for example, in US Pat.
Nos. 70,173 and 4,202,675, which are conventionally known processes.

FIG. 2 shows a developing section of the electrophotographic apparatus according to the first embodiment of the present invention. FIG. 2A is a front view, and FIG.
(B) is a side view. In FIG. 2, a developing device 4 arranged around the photosensitive drum 1 includes a developing roller 10, a liquid developer primary storage unit 11 arranged laterally parallel to the axis of the developing roller 10, and one end of a liquid developer. Developer primary storage unit 1
1 and the other end of the developing roller 10
Supply blade 12 arranged in contact with or close to
And

Two supply pipes 13 are connected to the bottom of the liquid developer primary storage section 11, and a liquid developer adjusted to a predetermined concentration from a liquid developer tank (not shown) passes through the pipe 13. The developer is supplied to the primary storage unit 11. The liquid developer is supplied by a pump (not shown) or the like, and the liquid developer is supplied to the liquid developer primary storage unit 11 or the liquid developer remaining in the liquid developer primary storage unit 11 is collected. Can also be performed by this pump.

Developing roller 1 of liquid developer primary storage section 11
The side surface on the 0 side has a lower wall height than other portions, and one end of the supply blade 12 is attached to the edge thereof. As described above, the blade 12 is arranged so that the other end thereof is in contact with or close to the generatrix of the developing roller 10, and has a surface such that it descends obliquely from the liquid developer primary storage unit 11 toward the developing roller 10. It is inclined.

For example, the developing roller 3 of the supply blade 12
If the portion near 0 is made of an elastic body such as oil-resistant smooth urethane rubber, the supply blade 12 can be brought into contact with the surface of the developing roller 10 with a considerably strong force.
By doing so, the supply blade 12 can also be used as a cleaning blade. In addition, the supply blade 12 can be disposed with a slight gap between the supply blade 12 and the developing roller 10.

The primary storage section 11 and the supply blade 12 are arranged near the developing roller 10 with a width at least equal to or larger than the image forming portion on the developing roller 10. The developing roller 10 is rotatably held in the developing container 14 by a drive source (not shown). Further, a pipe for collecting an excess liquid developer is attached to a lower portion of the developing container 14.

FIG. 2B shows the liquid developer primary storage unit 11.
FIG. 3 is a diagram viewed from a direction perpendicular to the rotation axis of the developing roller 30. A plurality of (two in the figure) supply pipes 13 are connected to the bottom surface of the liquid developer primary storage unit 11. Although it is possible to provide a larger number of pipes 13, there is a drawback that the mechanism is complicated, and it is preferable to use as few pipes as possible.

In the developing device configured as described above, development is performed by rotating the developing roller 10 in the direction indicated by the arrow in the figure. At this time, the pump not shown
Through the supply pipe 13 to the liquid developer primary storage unit 11,
The liquid developer is sent out at a predetermined rate per unit time. When the liquid developer is sent to the liquid developer primary storage unit 11,
The liquid level in the reservoir 11 rises immediately and the supply blade 12
It overflows from the side surface. At this time, regardless of the position of the pipe 13, the liquid developer overflows uniformly over the entire width of the supply blade 12, so that the liquid developer flows almost uniformly in the width direction toward the developing roller 10, and the supply blade 12 and the developing roller 10 To form a pseudo-triangular liquid developer reservoir.

The liquid developer pool is stored in the developing roller 10
Since there is no cover in the axial direction, the liquid developer leaks from this axial portion. The liquid level of the liquid developer pool is
It is determined by the amount of liquid developer supplied from the liquid developer primary storage unit 11 per unit time, the amount of liquid developer leaking from the liquid developer reservoir, and the amount of liquid developer attached to the developing roller 10 and carried to the developing unit. You.

When the liquid level of the liquid developer reservoir increases, the amount of leaked liquid developer also increases, and the liquid level of the liquid developer reservoir is determined uniquely. The amount of the liquid developer per unit time which adheres to the surface of the developing roller 10 and is transported to the developing unit is represented by the contact width (wetting width) of the liquid developer in the drawing,
And the rotation speed of the developing roller 10. The contact width of the liquid developer is determined by the liquid level of the liquid developer reservoir.

From the above, if the rotation speed of the developing roller 10 and the supply amount of the liquid developer per unit time are set to predetermined values,
An arbitrary contact width and the amount of the liquid developer adhering to the developing roller 10 can be obtained. Excess solvent leaked from the liquid developer reservoir is collected from the lower part of the developing container, and is again transported to the liquid developer supply unit by the pump.

In FIG. 2, the excess liquid developer remaining on the developing roller 10 after development is squeezed by the supply blade 12 and collected in the same manner. However, as shown in FIG. 20 may be provided and collected separately. This is related to the second embodiment of the present invention, and is effective when the surplus liquid developer after development needs to be cleaned in another step.

When the development is completed, the pump is reversed, and the excess liquid developer is promptly collected into the developing tank through the pipe 13 to evaporate the solvent from the remaining liquid developer and to transfer the toner to each part. Sticking and the like can be prevented.

FIG. 4 is a view showing a developing section of an electrophotographic apparatus according to a third embodiment of the present invention.
An example in which the liquid developer primary storage unit 11 is provided below both end surfaces is shown. FIG. 4A is a front view, and FIG. 4B is a side view.
In this manner, by supplying the liquid developer from both end surfaces of the liquid developer primary storage section 11, the liquid developer can be smoothly supplied without waving the liquid surface.

FIG. 5 is a view showing a developing section of an electrophotographic apparatus according to a fourth embodiment of the present invention.
3 shows an example in which the liquid developer 3 is provided at the lower part of the side surface of the liquid developer primary storage unit 11 opposite to the surface facing the developing roller 10. FIG. 5A is a front view, and FIG. 5B is a side view. By arranging the supply pipe 13 in this manner, the same effect as the example shown in FIG. 4 can be obtained.

FIG. 6 is a view showing an electrophotographic apparatus according to a fifth embodiment of the present invention, and shows an example in which the developing devices shown in FIG. 2 are arranged for each color. That is, the developing device 4 for yellow (Y)
a, each of a magenta (M) developing device 4b, a cyan (C) developing device 4c, and a black (K) developing device 4d was arranged to face the latent image holding member. Note that the developing devices 4a, 4
b, 4c, 4d, adjacent to the squeeze rollers 21a to 21c.
21d are arranged respectively. These squeeze rollers 21a to 21d are arranged to remove the solvent attached to the latent image holding member together with the toner fine particles.

Next, regarding the developing section of the electrophotographic apparatus according to the sixth embodiment of the present invention, the height of the liquid surface of the liquid developer reservoir, the contact width (wetting width) of the liquid developer, and the image density were measured. The relationship will be described with reference to FIG. First, the contact width (wetting width) of the liquid developer is proportional to the height of the liquid level in the liquid developer reservoir. Next, the image density is proportional to the contact width (wetting width) of the liquid developer. Accordingly, the image density is proportional to the liquid level of the liquid developer reservoir. Further, the height of the liquid level in the liquid developer reservoir changes depending on the supply speed of the liquid developer supplied to the liquid developer primary storage unit 11. Therefore, it is possible to control the image density by controlling the supply speed of the liquid developer.

That is, a sensor for detecting the level of the liquid level in the liquid developer pool is installed, and the sensor detects the level of the liquid level in the liquid developer pool to control the supply speed of the liquid developer. Thus, a predetermined image density can be always maintained. Further, it is possible to easily control the density of the image density.

In the embodiment of the present invention described above, the supply of the liquid developer to the developing roller 30 can be performed uniformly in the width direction. Further, by providing the supply buffer section (primary liquid developer storage section) which is a temporary storage section, the influence of pulsation of a pump or the like can be reduced as compared with the case where the supply is directly performed without the supply buffer section. Furthermore, since the amount of liquid developer adhering to the developing roller 30 during development can be set arbitrarily, a sufficient amount of liquid developer necessary for development can be supplied stably, and moreover, There is no need to circulate a large amount of solvent, and efficient development is possible.

The primary storage section does not need to be immersed in the developing roller 30, so that it can be made extremely small. In addition, there is no need for a detection mechanism for detecting the liquid level of the liquid developer, etc.
With a simple configuration, the above effects can be realized with a minimum number of control elements. Further, unnecessary evaporation of the solvent from the liquid developer can be suppressed to a minimum.

[0050]

As described above, according to the present invention,
An electrophotographic apparatus capable of stably supplying a necessary and sufficient amount of liquid developer to the developing unit during electrophotographic development in which liquid development is performed, thereby stabilizing an image can be obtained. Moreover, the apparatus has a very small number of control elements, a simple configuration, and very little evaporation of the solvent from the liquid developer. In addition, it is not necessary to provide a large liquid developer reservoir as in the related art, and it is only necessary to circulate the minimum necessary amount of liquid developer, which is extremely efficient.

As described above, according to the present invention, stable development can be performed with a simple structure, the evaporation of the solvent is small,
Further, a developing device capable of efficiently using the liquid developer can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an image forming unit of an electrophotographic apparatus according to an embodiment of the present invention.

FIG. 2 is a view showing a developing unit of the electrophotographic apparatus according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating a developing unit of an electrophotographic apparatus according to a second embodiment of the present invention.

FIG. 4 is a diagram illustrating a developing unit of an electrophotographic apparatus according to a third embodiment of the present invention.

FIG. 5 is a diagram illustrating a developing unit of an electrophotographic apparatus according to a fourth embodiment of the present invention.

FIG. 6 is a diagram illustrating an image forming unit of an electrophotographic apparatus according to a fifth embodiment of the present invention.

FIG. 7 is a diagram illustrating a developing unit of an electrophotographic apparatus according to a sixth embodiment of the present invention.

FIG. 8 is a diagram illustrating a configuration example of a developing device of a conventional electrophotographic apparatus.

FIG. 9 is a diagram illustrating a configuration example of a developing device of a conventional electrophotographic apparatus.

FIG. 10 is a diagram illustrating a configuration example of a developing device of a conventional electrophotographic apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Latent image holding body (photosensitive drum) 2a, 2b, 2c, 2d ... Charger 3a, 3b, 3c, 3d ... Laser exposure 4a, 4b, 4c, 4d ... Developing device 5 ... Transfer device 6 ... Intermediate transfer member 7 ... Pressure roller 8 ... Cleaner 9 ... Paper 10 ... Development roller 11 ... Liquid developer primary storage unit 12 ... Liquid developer supply blade 13 ... Liquid developer supply / recovery pipe 14 ... Development container 20 ... Cleaning blade 30 ... Development roller 31: photosensitive drum 30: blade

Claims (4)

[Claims] 1. An electrophotographic apparatus comprising: a latent image forming unit that forms a latent image on a latent image holding member; and a developing unit that supplies a liquid developer to the latent image to visualize the latent image. A developing unit comprising: a developer carrier that carries the liquid developer; and a unit that supplies the liquid developer to the developer carrier. The unit that supplies the liquid developer includes the latent image holder And a liquid developer primary storage section having a width substantially equal to or larger than the width of the latent image forming surface of the latent image holding member, and the latent image of the liquid developer primary storage section An electrophotographic apparatus comprising: a guideway for guiding the liquid developer overflowing on the side of the holder to the developer carrier. 2. The liquid developer primary storage section has a liquid developer inlet on a side surface or a bottom surface and a liquid developer recovery port on a bottom surface, and the liquid developer is introduced from the liquid developer inlet. 2. The electrophotographic apparatus according to claim 1, wherein the operation is performed at the start of printing, and the recovery of the liquid liquid developer from the liquid developer recovery port is performed when the printing operation is stopped. 3. The liquid level of the developer carrying member overflowing from the liquid developer primary storage section and flowing into the liquid developer reservoir surrounded by the conduit and the developer carrying member through the conduit. The apparatus further comprises means for detecting a height, and by controlling a supply rate of the liquid developer supplied to the liquid developer primary storage section, the liquid level of the liquid developer reservoir is maintained at a constant level. The electrophotographic apparatus according to any one of claims 1 to 4, wherein a predetermined image density is maintained thereby. 4. A latent image forming means for forming a latent image on a latent image holding member, and supplying a liquid developer to the latent image to visualize the latent image.
A liquid developer supply device for an electrophotographic apparatus, comprising: a developing unit having a developer carrying member for carrying the liquid developer; A liquid developer primary storage section having a width substantially equal to or wider than the width of the latent image forming surface of the body; and the liquid developer overflowing on the latent image holding body side of the liquid developer primary storage section. And a guide path leading to the developer carrier.