JP2005010626A - Liquid developing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid developing apparatus capable of obtaining an image with little unevenness in density by suppressing the unevenness in concentration of the liquid developer on the developing roll after developing due to following rotation and reducing nonuniformity in toner concentration of the liquid developer in a developing tank. <P>SOLUTION: In the developing device, the residual liquid developer on a developer carrier is recovered to a residual liquid recovery tank, which is different from the developer tank feeding the liquid developer to the developing roll 22 and the unevenness in concentration due to following rotation of the liquid developer on the developing roll 22 after developing is suppressed. Furthermore, a feeding mechanism and recovery mechanism of the liquid developer are provided in the developing tank on both end parts of the developing roll in the longitudinal direction. By circulating and agitating the liquid developer inside the developing tank, toner concentration unevenness in the developer liquid tank can be suppressed, the occurrence of unevenness in concentration of the liquid developer carried on the developer carrier can be prevented and moreover, the image with little unevenness in density can be obtained. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid developing apparatus that develops an electrostatic latent image formed on a latent image carrier with toner dispersed in a medium liquid.
[0002]
[Prior art]
A wet electrophotographic apparatus using a liquid developer has advantages that cannot be realized by a dry electrophotographic apparatus, and its value is being reviewed in recent years. In other words, in wet electrophotographic devices, submicron sized toner can be used, so high image quality can be achieved and the quality of printing can be obtained, and energy can be saved because toner can be fixed on paper at a relatively low temperature. , Etc.
[0003]
As a wet electrophotographic apparatus, a liquid developing apparatus in which an electrostatic latent image in electrophotography, electrostatic recording or the like is developed using a liquid developer containing toner particles and a medium liquid for dispersing the toner particles. It has been known.
[0004]
In such a liquid developing device, the liquid developer is once pumped from the developer tank storing the liquid developer for the purpose of preventing the carrier liquid as the medium liquid from excessively adhering to the surface of the latent image carrier. In addition, there is something that is developed after the development. For example, a developing roller for performing development is provided so as to face the latent image carrier, and a part of the developing roller is immersed in the liquid developer in the developer tank and rotated to rotate the liquid developer on the surface. And the like, and the liquid developer thus adhered is brought into contact with a latent image carrier to perform development.
[0005]
In such a developing device, normally, the liquid developer adhering to the developing roller is not completely consumed by the development and a part thereof remains on the developing roller. Therefore, the liquid developer remaining on the surface of the developing roller after passing through the developing area which is the opposite portion between the latent image carrier and the developing roller is scraped off by a cleaning blade and then dropped into the developer tank as it is. is there.
[0006]
However, when a low density image is formed, a large amount of toner remains on the developing roller, and when a high density image is formed, a large amount of medium liquid remains on the developing roller. When mixed in the liquid developer, density unevenness occurs in the liquid developer in the developer tank. Then, the density unevenness of the liquid developer in such a developer tank leads to the density unevenness of the liquid developer carried on the developing roller, and as a result, the density of the finally obtained image is uneven. There was a problem.
[0007]
In particular, when the toner is attracted to the surface of the developing roller by applying electrostatic force to the developing roller, the concentration of the liquid developer toner adhering to the surface of the developing roller is very high. Therefore, a large amount of toner remains on the surface of the developing roller even after passing through the developing region, and the degree of density unevenness of the liquid developer in the developer tank is increased, and the liquid developer carried on the developing roller is increased. The density unevenness was remarkable.
[0008]
In view of such problems, the following proposal has been made in Japanese Patent Application Laid-Open No. 8-110707. A feature of Japanese Patent Application Laid-Open No. 8-110707 is that it includes a collecting means for collecting the liquid developer remaining on the developing roller after being subjected to development so as not to fall directly into the developer tank. .
[0009]
As a result, by suppressing the density unevenness of the liquid developer in the developer tank, the occurrence of the density unevenness of the liquid developer carried on the developer carrier is prevented. Can be obtained.
[0010]
[Problems to be solved by the invention]
However, the following problems remain even when the above measures are used.
[0011]
If the liquid developer prepared by dispersing the carrier liquid and toner particles in the developing tank is left for a long time, the carrier liquid and the toner particles may be separated or the toner distribution may be non-uniform. In addition, since the liquid developer consumes toner particles or carrier liquid by development, it is necessary to readjust the toner particles and carrier liquid. For this purpose, the liquid developer in the developer tank and the replenished replenishment are required. It is necessary to mix uniformly with the replenishing toner or the replenishing carrier liquid. In such a case, it is not easy to uniformly mix the liquid developer adjusted to a high viscosity or a high concentration of, for example, 100 to 10,000 mPa · s, and the toner is uniformly mixed in the carrier liquid. I couldn't. In particular, when only one toner or carrier liquid supply point is provided from the viewpoint of ease of control and cost reduction, it is difficult to make the developing roller thrust direction uniform.
[0012]
For the above reasons, when the toner distribution of the liquid developer in the developer tank supplied to the developing roller becomes non-uniform, the liquid developer having a non-uniform toner concentration is supplied to the developing roller. The image quality may be degraded.
[0013]
As a result, as described above, even if the non-uniform liquid developer having a non-uniform density remaining after development on the developing roller is not mixed into the developer tank, a desired image cannot be obtained as described above. Can happen.
[0014]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to suppress density unevenness due to the swirling of the liquid developer after development on the developing roller, reduce non-uniformity of the toner concentration of the liquid developer in the developing tank, and produce an image with less density unevenness. It is an object to provide a liquid developing device that can be obtained.
[0015]
[Means for Solving the Problems]
In order to achieve the above object, the present invention develops an electrostatic latent image formed on the surface of a latent image carrier using a liquid developer containing toner particles and a medium liquid for dispersing the toner particles. In the liquid developing apparatus, the developer tank for storing the liquid developer and the liquid developer in the developer tank above the developer tank are carried on the surface, and this is carried on the surface of the latent image carrier. A developer carrying member that performs development in contact with the developer, and a residual liquid collecting unit that collects the liquid developer remaining on the developer carrying member after being subjected to development so as not to fall directly into the developer tank; and A developer supply means for supplying a liquid developer to the developer tank; and a developer recovery means for recovering the liquid developer from the developer tank. The developer supply means is arranged at a longitudinal end of the developer carrier. The developer collecting means is disposed in the vicinity of the developer carrying portion of the developer. Wherein said that the developer is disposed near an end portion that is different from the supply means.
[0016]
It is desirable that the developer supply means and the developer recovery means are arranged opposite to each other outside the image area in the longitudinal direction of the developer carrier.
[0017]
It is desirable to provide a stirring means for stirring the liquid developer in the developer tank.
[0018]
A screw can be used as the stirring means.
[0019]
It is desirable to dispose the residual liquid collecting means in the vicinity of the developer collecting means.
[0020]
It is desirable to provide toner particle replenishing means for replenishing the replenishing toner particles and / or medium liquid replenishing means for replenishing the replenishing medium liquid in the vicinity of the residual liquid collecting means.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
(Example 1)
Hereinafter, the present invention will be described in detail by way of examples.
[0022]
FIG. 1 is a cross-sectional view of an electrophotographic full color printer 100 incorporating a liquid developing apparatus to which the present invention is applied. As shown in FIG. 1, inside a printer 100, a cylindrical photosensitive drum 1 on which an electrostatic latent image is formed is provided so as to be rotatable in the direction of arrow a shown in the drawing. . As the photoreceptor 1, a photoreceptor drum having a structure in which an organic or amorphous silicon photosensitive layer is provided on a conductive substrate may be used. Around the photosensitive member 1, a laser generator 3 that generates an image-modulated laser beam, a liquid developing device 20 that is a process device for image formation, a squeeze roller 4, an intermediate transfer medium 5, a cleaner 6, and a charging Containers 2 are arranged sequentially. The full color printer 100 according to the present embodiment includes four color liquid developing devices 20Y, 20M, 20C, and 20K of Y, M, C, and Bk as the liquid developing device 20, and each of yellow (Y) in a full color image. , Magenta (M), cyan (C), and black (Bk) images are formed. The Y, M, C, and Bk liquid developing devices have substantially the same configuration. (In the following description, for example, with the liquid developing device 20, the Y, M, C, and Bk liquid developing devices 20Y, 20M, 20C, and 20K may be commonly referred to.) Also, the printer 100 side. The part is provided with a pressure roller 7 for fixing the toner image formed on the paper 8 from the intermediate transfer medium.
[0023]
The printing operation of the printer 1000 is performed as follows. The photosensitive drum 1 starts to rotate in the direction of arrow a at a predetermined speed, and is uniformly charged by the charger 2, and then irradiated with a laser beam from the laser generator 3, thereby causing electrostatic latent image on the surface. An image is formed. As the charger 2, a known corona charger, scorotron charger, or the like may be used. The electrostatic latent image is visualized as an image of the first color using the liquid developer by the liquid developing device 20Y, and then the medium liquid excessively adhered is squeezed out by the squeeze roller 4.
[0024]
The visible image made of toner particles formed on the surface of the photosensitive drum 1 is transferred to an intermediate transfer medium 5 having, for example, a belt shape or a drum shape (in the present embodiment, a drum shape), and then the charger 2 and the laser generator 3. Then, an electrostatic latent image of the second color is formed, and the second color is developed by the liquid developing device 20M and transferred to the intermediate transfer medium 5. Similarly, third and fourth developments are performed, and transfer to the intermediate transfer medium 5 is performed. In the transfer, either transfer by electric field or transfer by pressure can be used. The full-color image formed on the intermediate transfer medium 5 is fixed to a recording medium 8 such as a sheet by a pressure roller disposed on the intermediate transfer medium 5 from 7. Heat may be applied to the pressure roller as necessary.
[0025]
Further, the toner that cannot be transferred to the intermediate transfer medium 5 and remains on the photosensitive drum 1 is removed by the cleaner 6, and the photosensitive drum 1 is subjected to the next image forming process. Thus, a series of printing operations is completed.
[0026]
In the wet electrophotographic apparatus shown in FIG. 1, the present invention is characterized by the liquid developing apparatus 20. FIG. 2 shows an enlarged view of the liquid developing apparatus 20 and will be described in more detail.
[0027]
As shown in FIG. 2, the liquid developing device 20 includes a developer storage tank 40 for storing the liquid developer, a liquid supply device 31 such as a pump for pumping up the liquid developer in the developer storage tank 40, and a photoconductor. A developing head 21 that faces the drum 1 and develops the electrostatic latent image on the photoreceptor 1 with a liquid developer supplied by a liquid supply device 31 is provided.
[0028]
The developing head 21 includes a developing roller 22 for supporting a liquid developer on a surface thereof, a frame 23 for supporting the developing roller 22, a developer tank 24 for storing the liquid developer, and a developer tank 24. Partition wall 25 for keeping the surface of the liquid developer constant, liquid recovery tank 26 for recovering the liquid developer overflowing from the developer tank 24, and scraping off the liquid developer remaining on the developing roller 22. A cleaning blade 28 and a residual liquid collection tank 27 for collecting the liquid developer scraped by the cleaning blade 28 are provided.
[0029]
The developing roller 22 is a metal cylindrical column, and is arranged in parallel with the longitudinal direction of the photosensitive drum 1. The developing roller 22 is arranged in the direction of the arrow b in FIG. , The developing unit c) is supported so as to be rotatable in the same direction as the direction of rotation of the photoreceptor 1 (arrow a).
[0030]
An interval between the photosensitive member 1 and the developing roller 22 (hereinafter referred to as a developing gap) in the developing unit c can be arbitrarily set within a range of 0 to 2 mm. When the development gap is 0.1 to 2 mm, it is advantageous in terms of background fogging as will be described later.
When the photosensitive drum 1 and the developing roller 22 are in contact with each other without providing a developing gap, it is advantageous in terms of high-speed development.
[0031]
The developer tank 24 is provided below the developing roller 22. A liquid supply port 31 connected to a liquid supply device 31 is formed at the bottom of the developer tank 24. When developing, liquid development is performed from the liquid supply port 31 to the developer tank 24 by the liquid supply device 32. As shown in FIG. 2, the lower part of the developing roller 22 is immersed in the liquid developer in the developer tank 24.
[0032]
A part of the upper end of the wall surface forming the developer tank 24 is kept constant by the partition wall 25 so as to be adjacent to the lower part of the developing roller 22, and the excess liquid developer is stored in the partition wall 25. Overflowing from.
[0033]
The liquid recovery tank 26 is provided adjacent to the partition wall 25, and the liquid developer flows from the developer tank 24 over the partition wall 25 into the liquid recovery tank 26. A liquid recovery port 33 is formed at the bottom of the liquid recovery tank 26, and the liquid developer flowing into the liquid recovery tank 26 is recovered from the liquid recovery port 33 and returned to the developer storage tank 40. In this embodiment, the liquid is collected using gravity, but the liquid collecting device may be connected to the tip of the liquid collecting port to collect the developer. What is necessary is just to use a pump etc. as a liquid collection | recovery apparatus.
[0034]
The residual liquid recovery tank 27 is provided adjacent to the liquid recovery tank 26 on the side opposite to the developer tank 24. A residual liquid recovery port 34 is formed at the bottom of the residual liquid recovery tank 27, and the liquid developer flowing into the residual liquid recovery tank 27 is recovered from the residual liquid recovery port 34 and returned to the developer storage tank 40. Similarly to the case of the liquid recovery port 33, a residual liquid recovery device may be provided.
[0035]
The residual liquid recovery tank 27 is preferably provided adjacent to the liquid recovery tank 26 instead of the developer tank 24 as in the configuration of the present embodiment. This is because if a liquid developer having a low toner concentration that should be collected in the residual liquid collection tank 27 passes through the cleaning blade 28 or the partition plate 29 and enters the adjacent liquid collection tank 26, the liquid collection tank 26 If there is no problem, the developer storage tank 40 can be returned to the developing solution storage tank 40 as it is, but there is a possibility that a liquid developer having a low toner concentration may be supplied again to the developing roller when the developer tank 24 is next. Further, when the residual liquid recovery tank 27 and the developer tank 24 are adjacent to each other, a part where the residual liquid after development is recovered in the developer storage tank 40 and a part where the developer for supplying to the developer tank is pumped up. In such a case, the liquid developer having a low toner density after development tends to be pumped up to the developer tank 24 as it is.
[0036]
The cleaning blade 28 is made of polyurethane rubber and is attached to the tip of the partition plate 29. The tip of the cleaning blade 28 is in contact with the surface of the developing roller 22 so as to face the roller rotating direction, and scrapes off the liquid developer remaining on the developing roller 22. The liquid developer thus scraped off is guided to the residual liquid recovery tank 27 through the cleaning blade 28 and the partition plate 29.
[0037]
When the developing roller 22 is made of a hard material such as a metal or a high hardness resin, the cleaning blade 28 may be made of a flexible material such as a rubber blade. In particular, a polyurethane rubber blade is preferable. If the developing roller is made of a flexible material such as an NBR (nitrile rubber) roller, a cleaning blade made of a hard material such as a metal blade, a resin blade, or a ceramic blade is used. do it. Also. Instead of the cleaning blade 28, a cleaning roller or the like may be used.
[0038]
Note that. Above the liquid recovery tank 24, there is provided a liquid draining member 30 for cutting off a part of the liquid developer carried on the developing roller 22 and reducing it to a predetermined amount.
[0039]
Next, the operation of the liquid developing device 20 will be described in detail. When the development is started, the liquid supply device 32 operates to supply the liquid developer from the liquid supply port 31 to the developer tank 24. With the start of development, the developing roller 22 also starts to rotate in the direction of arrow b, and a liquid developer layer is formed on the developing roller 22. The liquid developer layer is transported to the developing unit c after a part of the medium liquid layer is cut off by the liquid cutting member 30 by the rotation of the developing roller 22.
[0040]
At this time, as known in the art, a thin layer forming electrode is provided facing the developing roller 202, a voltage is applied to the developing roller, and the toner is attracted to the developing roller surface by electrostatic force. Although the concentration of the liquid developer toner that adheres can be very high, a large amount of toner remains on the surface of the developing roller even after passing through the development area, and the degree of density unevenness of the liquid developer in the developer tank And the density unevenness of the liquid developer carried on the developing roller became remarkable. Even in such a case, this configuration is effective.
[0041]
A predetermined developing bias is applied to the developing roller 22 on which the liquid developer layer is formed, and the toner is exposed from the developing roller 22 by being attracted to the electric field by the electrostatic latent image on the photosensitive member 1 in the developing unit c. The electrostatic latent image is developed by migrating onto the body 1 and adhering to the latent image surface by Coulomb force.
[0042]
In particular, when the development gap is 0.1 to 2 mm, the medium liquid layer of the liquid developer layer carried on the developing roller 22 comes into contact with the surface of the photoreceptor 1, and the toner is transferred from the toner thin layer to the medium liquid layer. Therefore, the toner thin layer does not come into direct contact with the photoconductor 1 and the occurrence of background fogging can be suppressed.
[0043]
The developer remaining on the developing roller 22 after passing through the developing portion c is scraped off by the cleaning blade 28. The developer scraped off by the cleaning blade 28 flows into the residual liquid recovery tank 27 through the partition plate 29. Therefore, the developer remaining on the developing roller 22 does not flow directly into the developer tank 24 and change the toner concentration of the liquid developer in the developer tank 24.
[0044]
The liquid developer flowing into the residual liquid recovery tank 27 is recovered from the residual liquid recovery port 34 and returned to the developer storage tank 40.
[0045]
As described above, the liquid developer on the developing roller 22 after the development is not returned directly to the developer tank 24, but is collected in the remaining liquid collection tank 27, whereby the density unevenness of the liquid developer in the developer tank is recovered. And the occurrence of density unevenness of the liquid developer carried on the developer carrying member can be prevented, and as a result, an image having no density unevenness can be finally obtained.
[0046]
However, as described in the problem to be solved by the invention, the following problems remain.
That is, since the liquid developer consumes toner particles or carrier liquid by development, it is necessary to replenish the toner particles and carrier liquid. However, when the replenishment place is in the developer tank 24, the toner particles and carrier liquid are required. The concentration of the liquid developer changes only in the vicinity of the replenishment location, and the toner concentration in the developer tank 24 may become uneven in the longitudinal direction of the developing roller 22. Further, when toner particles and carrier liquid are replenished in the developer storage tank 40 and the liquid developer is pumped into the developer tank 24, the vicinity of the liquid supply port 31 from the developer storage tank 40 to the developer tank 24 is also provided. It is likely that the concentration of only the liquid developer changes and the liquid developer far from the liquid supply port 31 does not change. This is because, for example, when a liquid developer adjusted to a high viscosity or a high concentration of, for example, 100 to 10000 mPa · s is used, mixing is not easy and the thrust direction of the developing roller is made uniform. Is difficult. In addition, a problem is likely to occur particularly when the toner or carrier liquid replenishment location and the liquid supply port 31 from the developer storage tank 40 to the developer reservoir 24 are provided at only one location from the viewpoint of ease of control and cost reduction. Even if a large number of replenishment points and liquid supply ports 31 are provided, it does not disappear.
[0047]
Therefore, a feature of the present invention is that a liquid circulation port 35 is provided in the developer tank 24 together with the liquid supply port 31, and FIG. 3 shows a sectional view in the longitudinal direction of the developing roll 22 of the liquid developing device 20. However, the liquid supply port 31 and the liquid circulation port 35 are disposed apart from each other at both ends in the longitudinal direction of the developing roll 22 in the developer tank 24. The operation of the liquid developing apparatus of the present invention will be described below with reference to FIG.
[0048]
A liquid supply device 32 such as a pump for pumping up the liquid developer in the developer storage tank 40 is disposed in the developer supply path to the developer tank 24. From the developer tank 24 to the developer storage tank 40, a liquid supply device 32 is provided. A liquid circulation device 36 is also attached to the liquid circulation port 35, and the liquid developer in the developer tank 24 is returned to the developer storage tank 40. As the liquid circulation device 36, a power source such as a pump may be used. By providing the liquid circulation port 35 and the liquid circulation device 36, the liquid developer pumped up by the liquid supply device 32 to the developer tank 24 is conveyed in the developer tank 24 in the longitudinal direction of the developing roll 22, and the liquid circulation A flow occurs in the liquid developer in the developer tank 24 so as to return to the developer storage tank from the port 35, and as a result, it is possible to reduce unevenness in the toner concentration of the liquid developer in the developer tank 24. Become. At this time, the liquid supply port 31 and the liquid circulation port 35 should be arranged as far apart as possible in the longitudinal direction of the developing roll 22, and preferably provided outside the image area related to image formation of the developing roll 22, In addition, the liquid developer staying portion can be eliminated, and density unevenness can be reduced.
[0049]
Further, if the supply capacity of the liquid supply device 32 to the developer tank 24 is made larger than the recovery capacity from the developer tank 24 of the liquid circulation device 36, the developer can be smoothly circulated in the longitudinal direction of the developing roll 22. As a result, toner density unevenness of the liquid developer is further reduced, and the developer surface in the developer tank 24 can be maintained. At this time, the liquid developer excessively supplied beyond the ideal developer surface overflows from the partition wall 25 through the liquid recovery tank 26 and the liquid recovery port 33 as described above with reference to FIG. Collected in storage tank. Even if the supply capability of the liquid supply device 32 is made larger than the recovery capability of the liquid circulation device 36, only the amount of liquid developer overflowing from the partition wall is increased, so it is meaningless to merely use energy wastefully. The ratio A / B of the supply amount A per unit time of the liquid supply device 32 and the recovery amount B per unit time of the liquid circulation device 36 is preferably in the range of 1.1 to 1.5.
[0050]
As for the stabilization of the liquid surface, a method of feeding back to the supply capability of the liquid supply device 32 and the recovery capability of the liquid circulation device 36 using a sensor or the like without using the partition wall 25 as in this embodiment may be used. The configuration is slightly complicated. If the supply capability of the liquid supply device 32 and the recovery capability of the liquid circulation device 36 are finely adjusted, a configuration without a sensor is possible, but there is a possibility that it will not be possible to deal with when an accident occurs. In addition, the position of the partition wall 25 of the present embodiment is not limited to the position of the present embodiment as long as the object is achieved.
[0051]
Although the liquid circulation port 35 is not provided with the liquid circulation device 36 and the liquid developer in the developer tank 24 is collected by its own weight, the object of this patent can be achieved. However, by providing the liquid circulation device, The operation can be stabilized.
[0052]
Here, if toner particles and carrier liquid are replenished, as described above, since toner particles or carrier liquid is consumed by development, it is necessary to readjust the toner particles and carrier liquid. The position is best provided in the vicinity of the residual liquid collection port 34. This is because the liquid developer with a low toner concentration recovered from the developed roller 22 after the development is recovered from the residual liquid recovery port 34, so the toner particle and carrier liquid supply ports 41 and 42 are in the vicinity of this. It is preferable to relax the developer concentration. The residual liquid collection port 34 is preferably arranged as far as possible from the liquid supply port 31 in order to prevent the liquid developer having a low toner concentration from being immediately drawn into the developing tank. With this arrangement, the supplied toner and the low-concentration liquid developer collected from the developing roller 22 are sufficiently mixed in the developer storage tank 40 before reaching the pumping port 31, and the developer tank. 24, the toner density unevenness of the liquid developer in the developer tank 24 can be further reduced.
[0053]
(Example 2)
The configuration and operation of the second embodiment are almost the same as those of the first embodiment except for the points described in detail below.
[0054]
The feature of the second embodiment is that, in contrast to the configuration of the first embodiment, as shown in FIGS. 4 and 5, a screw that is a stirring member for a liquid developer in the developer tank 24 parallel to the thrust direction of the developing roll 22. 50 is a part added to the first embodiment. By rotating the screw 50 in the direction of the arrow d in FIG. 4, the liquid developer in the developer tank 24 is more actively circulated, and the toner density unevenness in the thrust direction can be reduced, and the screw 50 is agitated. Thus, toner density unevenness other than in the thrust direction can be made uniform by mixing the liquid developer. Also, if the liquid developer prepared by dispersing the carrier liquid and toner particles in the developer tank is left for a long time, the carrier liquid and toner particles may be separated. The member 50 is particularly effective.
[0055]
The stirring member 50 is not required to have a conveying ability such as a screw, and it is possible to perform only stirring using a paddle-shaped member.
[0056]
Also, providing such a stirring member in the developer storage tank 40 is effective in mixing the replenished toner and the liquid developer having a low toner concentration from the residual liquid recovery port 34.
[0057]
In this embodiment, the full-color image forming apparatus is described. However, it is needless to say that the present invention is effective for a single-color image forming apparatus.
[0058]
【The invention's effect】
As described above, in the present invention, the liquid developer remaining on the developer carrying member is collected in a residual liquid collecting tank different from the developer tank for supplying the liquid developer to the developing roll, and developed on the developing roller. In addition to suppressing density unevenness due to the trailing of the liquid developer, it is equipped with a liquid developer supply mechanism and a recovery mechanism at both ends in the longitudinal direction of the developing roller in the developer tank, to circulate and agitate the liquid developer in the developer tank. By doing so, it is possible to suppress toner density unevenness in the developer tank, to prevent occurrence of density unevenness of the liquid developer carried on the developer carrier, and to obtain an image with less density unevenness. it can.
[Brief description of the drawings]
FIG. 1 is a schematic view of a wet electrophotographic apparatus of the present invention.
FIG. 2 is an enlarged view of a developing device used in the wet electrophotographic apparatus according to the first embodiment of the present invention.
FIG. 3 is a longitudinal sectional view of a developing roller of a developing device used in a wet electrophotographic apparatus according to a first embodiment of the present invention.
FIG. 4 is an enlarged view of a developing device used in a wet electrophotographic apparatus according to a second embodiment of the present invention.
FIG. 5 is a longitudinal sectional view of a developing roller of a developing device used in a wet electrophotographic apparatus according to a second embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Photoconductor 20 Liquid developing device 21 Developing head 22 Developing roller 24 Developer liquid tank 26 Liquid recovery tank 27 Residual liquid recovery tank 28 Cleaning blade 31 Liquid supply port 33 Liquid recovery port 34 Residual liquid recovery port 35 Liquid circulation port 40 Developer storage Tank 50 Agitating and conveying member 100 Wet electrophotographic apparatus

Claims (6)

In a liquid developing apparatus for developing an electrostatic latent image formed on the surface of a latent image carrier using a liquid developer containing toner particles and a medium liquid for dispersing the toner particles,
A developer tank for storing a liquid developer;
A developer carrier above the developer tank, carrying the liquid developer in the developer tank on the surface, and developing the liquid developer in contact with the surface of the latent image carrier;
Residual liquid recovery means for recovering the liquid developer remaining on the developer carrier after being subjected to development so as not to fall directly into the developer tank;
Developer supply means for supplying a liquid developer to the developer tank;
A developer recovery means for recovering the liquid developer from the developer tank;
The developer supply means is disposed in the vicinity of the end portion in the longitudinal direction of the developer carrier, and the developer recovery means is disposed in the vicinity of an end portion different from the developer supply means of the developer carrier. A liquid developing apparatus characterized by the above. The liquid developing apparatus according to claim 1, wherein the developer supplying unit and the developer collecting unit are arranged to face each other outside an image area in a longitudinal direction of the developer carrying member. The liquid developing apparatus according to claim 1, wherein a stirring unit that stirs the liquid developer is provided in the developer tank. The liquid developing apparatus according to claim 3, wherein a screw is used as the stirring means. 5. The liquid developing apparatus according to claim 1, wherein the residual liquid collecting means is disposed in the vicinity of the developer collecting means. 6. The liquid according to claim 1, wherein toner particle replenishing means for replenishing replenishing toner particles and / or medium liquid replenishing means for replenishing replenishing medium liquid are provided in the vicinity of the residual liquid collecting means. Development device.

Images