JPH11288174A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device which achieves miniaturization, simplification, and cost reduction of a developing device. SOLUTION: As a developing sleeve 41, a hollow cylindrical member is used. In the hollow of the developing roller 41 composed of the cylindrical member, one drive roller 46, having a diameter smaller than the inside diameter of the developing sleeve 41, is freely rotatably disposed. A part of the internal circular face of the developing sleeve 41 is supported by the drive roller 46 so that it is free to rotate. Also, a cleaning blade 47 as a pressing member is disposed in firm contact with the external circular face of the developing roller 41 so as to exert pressure to the drive roller 46 via the developing roller 41.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a facsimile, and a printer.
After forming a thin layer of liquid developer on the developer carrier, and using the liquid developer on the developer carrier to visualize the electrostatic latent image on the latent image carrier, The present invention relates to an image forming apparatus for transferring an image to a transfer material.

[0002]

2. Description of the Related Art In this type of image forming apparatus, a developing device is used which develops an electrostatic latent image formed on a latent image carrier as an image support such as a photoreceptor by using toner as charged particles. ing. In order to reduce the size of the developing device, it has been proposed to use a high-concentration and high-viscosity developer in which the toner concentration of a developer in which toner is dispersed in an insulating liquid is set to be higher. For example, Japanese Patent Application Laid-Open No. 7-209922 discloses a liquid development method for an electrostatic latent image formed by developing an electrostatic latent image formed on an image support with toner, which is a charged visualized particle, By contacting the image support with a high-viscosity liquid developer of 100 to 10000 mPas in which toner is dispersed at a high concentration in an insulating liquid applied on a developer support having conductivity, A liquid developing method for an electrostatic latent image, comprising a developing step of supplying the liquid developer to a latent image surface of an image support.

As a developing device for visualizing an electrostatic latent image on the latent image carrier by using such a thin layer of liquid developer, for example, as shown in FIG. A developer carrier for supplying a liquid developer (hereinafter, simply referred to as a “developer”) to the photoconductor 1 as a carrier,
An endless belt-shaped developing belt 2 having flexibility;
The developing belt 2 is stretched around a driving roller 3 composed of a pair of belt rollers and a driven roller 4 to be rotationally driven.
A developing device configured to apply the developing solution 7 in the developing solution tank 6 to the developing belt 2 in a thin layer by the application roller 5;
Alternatively, as shown in FIG. 5, the developing belt 2 is directly immersed in the developing solution 7 in the developing solution tank 6 and the developing solution
There is known a developing device in which the developing device is pumped onto the developing belt 2. In FIG. 4, the excess developer 7 pumped up by the application roller 5 is supplied to the developing belt 2.
The developing solution 7 applied to the coating roller 5 is removed from the coating roller 5 by the metering blade 8 so that the layer thickness becomes a predetermined layer thickness. 4 and 5, the developing solution 7 applied to the developing belt 2 and supplied to the photoreceptor 1 to develop the latent image formed on the photoreceptor 1 includes a cleaning blade 9. As a result, the toner is removed from the developing belt 2.

[0004]

However, in a developing device using a flexible endless belt-shaped developing belt as a developer carrying member, the method of driving the developing belt becomes a problem. That is, as described above, in the case of a configuration in which the developing belt is driven by applying tension by a plurality of belt rollers, the rotation shaft of each belt roller is used to prevent the developing belt from shifting in the axial direction. It is necessary to keep the parallelism with high accuracy. For this reason, in an image forming apparatus having such a developing device, it is necessary to provide a belt roller shaft adjusting mechanism for preventing the developing belt from shifting in a supporting portion of a belt roller that stretches the developing belt. In addition, the structure for supporting the developing belt as a developer carrier and the driving system are complicated and costly. Further, in this image forming apparatus, a configuration in which a plurality of belt rollers are arranged in a developing belt of the developing apparatus and the number of components is large, and the developing apparatus itself becomes large, for example, as in a color image forming apparatus. In the case of an image forming apparatus having a plurality of developing devices, there is a problem that the entire image device becomes large.

The present invention has been made in view of the above problems, and has as its object to reduce the size of a developing device,
An object of the present invention is to provide an image forming apparatus that can be simplified and reduced in cost.

[0006]

In order to achieve the above object, an image forming apparatus according to claim 1 forms a liquid developer layer in which a toner is dispersed in a dielectric carrier liquid on a developer carrier, In an image forming apparatus for developing an electrostatic latent image on a latent image carrier by bringing a liquid developer on the developer carrier into contact with the latent image carrier on which an electrostatic latent image is formed, a hollow cylinder A developer carrying member formed of a cylindrical member, a driving roller rotatably disposed in a hollow portion of the developer carrying member for rotatably driving the developer carrying member, and driving the developer carrying member via the developer carrying member. And a pressing member arranged so as to press against the outer peripheral surface of the developer carrier so as to apply pressure to the roller.

In this image forming apparatus, the developer carrier is rotated by rotating the drive roller while the developer carrier is held between the drive roller and the pressing member. Therefore, in this image forming apparatus, the structure for supporting the developer carrier and the driving means can be simplified, the cost can be reduced, and the size of the developing device can be reduced.

According to a second aspect of the present invention, there is provided the image forming apparatus according to the first aspect, further comprising an application roller for applying the liquid developer to an outer peripheral surface of the developer carrier. is there.

In this image forming apparatus, since the developer is applied to the outer peripheral surface of the developer carrier by the application roller, the developer can be more uniformly applied to the developer carrier. .

According to a third aspect of the present invention, there is provided the image forming apparatus according to the first or second aspect, wherein an inner peripheral surface of the developer carrier and an outer peripheral surface of the driving roller are rotated when the driving roller rotates. When the frictional force of the contact portion is Fa and the frictional force of the contact portion between the outer peripheral surface of the developer carrier and the pressing member is Fb, the relationship between the frictional forces Fa and Fb is Fa> Fb. It is characterized by the following.

In this image forming apparatus, the frictional force Fa of the contact portion between the inner peripheral surface of the developer carrier and the outer peripheral surface of the drive roller when the drive roller rotates is determined by the friction force Fa of the developer carrier. Friction force F at the contact portion between the outer peripheral surface and the pressing member
b, the slip between the inner peripheral surface of the developer carrier and the outer peripheral surface of the drive roller during rotation of the drive roller is eliminated, and the latent image bearing by the developer carrier is eliminated. The developer can be reliably supplied to the body.

According to a fourth aspect of the present invention, there is provided the image forming apparatus according to the first or second aspect.
Alternatively, in the image forming apparatus according to the third aspect, a high friction member layer is provided on a portion or the entirety of an inner peripheral surface of the developer carrier that is rotated and driven in contact with the drive roller. .

In this image forming apparatus, the high friction member layer is provided on the inner peripheral surface of the developer carrier which is driven to rotate in contact with the drive roller. When the roller rotates, the inner peripheral surface of the developer carrier and the outer peripheral surface of the drive roller become less slippery, and the developer can be more reliably supplied to the latent image carrier by the developer carrier. Become like

According to a fifth aspect of the present invention, there is provided the image forming apparatus according to the first aspect.
In the image forming apparatus of 2, 3, or 4, the peripheral speed of the developer carrier at the time of rotation of the drive roller is Sa,
When the peripheral speed of the latent image carrier is Sb, the relationship between the peripheral speeds Sa and Sb is Sa ≧ Sb.

In this image forming apparatus, the peripheral speed Sa of the developer carrier during rotation of the drive roller is
Is set to a speed equal to or higher than the peripheral speed Sb of the latent image carrier, so that the amount of developer supplied per unit time by the developer carrier to the latent image carrier is insufficient. Therefore, a decrease in image density due to an insufficient supply amount of the developing solution is eliminated.

According to a sixth aspect of the present invention, there is provided the image forming apparatus according to the first aspect.
In the image forming apparatus of any one of 2, 3, 4 and 5, the pressing member is a cleaning blade for scraping a liquid developer supplied to a peripheral surface of the developer carrier. .

In this image forming apparatus, the pressing member is constituted by a cleaning blade for scraping off the liquid developer supplied to the peripheral surface of the developer carrier. The driving means can be configured more compactly and at lower cost.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to an electrophotographic copying machine (hereinafter simply referred to as a "copying machine") as an image forming apparatus will be described below.

As shown in FIG. 1, the copying machine according to this embodiment has a photosensitive drum 10 as a latent image carrier, a charging roller 20 as charging means for the photosensitive drum 10, and a latent image writing means. Exposure device 30, developing device 40 as developing means for the latent image, and transfer roller 5 as transferring means
0, a cleaning device 60 as cleaning means for the photosensitive drum 10, a static elimination device 70 as static elimination means for the photosensitive drum 10, and the like.

Further, the developing device 40 in the copying machine
Is a developing sleeve 41 as a developer carrier, and 100 to 1000 mP in which toner is dispersed in a dielectric carrier.
a · s, a developer tank 43 for storing a high-viscosity developer 42, an application roller 44 arranged so that the lower part is immersed in the developer 42 in the developer tank 43, and an application roller 44 A developing blade 42 for thinning the developing solution 42 pumped by the developing sleeve 41;
A driving roller 46 for rotationally driving the developer, and a developer 42 applied to the developing sleeve 41 by the applying roller 44.
And a cleaning blade 47 for scraping off the developing sleeve 41 from above. In the developing device 40, the developer is 100 to 1000 mP.
Although the high-viscosity developing solution 42 of a · s is used, it goes without saying that it is also possible to use a developing solution having a normal viscosity.

In FIG. 1, the photosensitive drum 10 is
The charging roller 20 is uniformly charged to a predetermined potential while being driven to rotate in the direction of the arrow. Thereafter, the reflected light from the original is image-formed and projected by an optical system (not shown) of the exposure device 30, so that a latent image corresponding to the image data is formed on the photosensitive drum 10. The latent image formed on the photosensitive drum 10 is transferred to the developing sleeve 4 of the developing device 40.
The photosensitive drum 10 and the developing sleeve 41 are thinly coated and thinned on the peripheral surface of the photosensitive drum 10 by a high-viscosity developer 42.
Is developed in the nip portion, and is visualized as a toner image.

The toner image visualized by the developing device 40 is transferred from a paper feeding device 80 including a paper feeding cassette 81, a paper feeding roller 82, a separation roller 83, and the like to the surface of the photosensitive drum 10 in an arrow direction. Transfer paper 84 conveyed to
Is transferred at a nip portion between the photosensitive drum 10 and the transfer roller 50. The transfer paper 84 onto which the toner image has been transferred is separated from the photosensitive drum 10 by a separating device (not shown), and is fixed by a fixing device 90 including a heating roller 91 and a pressure roller 92 as a fixing unit for the toner image. After the fixing process is performed, the sheet is discharged onto a tray (not shown) provided outside the apparatus main body.

On the other hand, when the toner image is transferred, the untransferred toner remaining on the photosensitive drum 10 without being transferred onto the transfer paper 84 is transferred onto the photosensitive drum 10 by the cleaning blade 61 of the cleaning device 60. And is collected in the developer collection container 62. And
In the photosensitive drum 10 from which the untransferred toner has been removed, the residual charge remaining on the latent image forming surface is discharged by the discharging device 70 in preparation for the next charging.

Here, the developing device 40 does not include the coating roller 44, and immerses the lower portion of the developing sleeve 41 in a developing solution reservoir as in the case of the developing device shown in FIG. It may be configured so that the developer 41 is directly pumped up by 41.

The developing solution tank 43 of the developing device 40 shown in FIG. 1 has the developing solution 42 disposed near the bottom thereof.
Is largely divided into two chambers, a developer supply chamber 43a and a developer recovery chamber 43b. The application roller 44 is provided with a developer supply chamber 43 provided on the developer discharge side of the gear pump 48.
The developing solution in the developing solution supply chamber 43 a, which is pushed up by the pressure of the gear pump 48, is supplied to the application roller 44. At this time, the excess developer not supplied on the peripheral surface of the application roller 44 is directly changed by the gravity of the developer to the developer recovery chamber 43 provided on the developer suction side of the gear pump 48.
b.

The developing roller 4 is applied to the developing sleeve 41 by the applying roller 44 and is not used for developing the latent image formed on the photosensitive drum 10.
1 is removed from the developing sleeve 41 by a cleaning blade 47, and the developer collecting chamber 4 on the developer suction side of the gear pump 48 is moved by gravity.
3b.

At this time, if the developing solution application surface (peripheral surface) of the developing sleeve 41 after the development of the latent image is not cleaned, the developing solution at a portion which is not consumed by the development of the latent image and which does not correspond to the latent image. Remains on the developing sleeve 41. Therefore, in this case, the developing sleeve 4
Even when a new developing solution is applied on the developing sleeve 1, the latent image is formed on a thin layer of the developing solution newly formed on the developing sleeve 41 due to the effect of the developing solution remaining on the developing sleeve 41. Since the residual developer remains as it is as a change in the layer thickness, the residual developer causes a ghost, and the image quality of the toner image transferred to the transfer paper 84 is significantly deteriorated.

On the other hand, the developing solution 42 is obtained by dispersing toner in a carrier liquid which is an insulating liquid.
If left for a long time, the carrier liquid and the toner may be separated, or the dispersion state of the toner in the carrier liquid may be uneven. Further, the cleaning blade 47 removes the toner from the developing sleeve 41,
The developer returned to the developer recovery chamber 43b has a toner concentration in the developer that changes in accordance with the image area ratio. It is necessary to readjust the toner density.

Therefore, in a developing device using such a developing solution 42, a stirring means for dispersing and mixing the toner in the carrier liquid is required in the developing solution tank 43. The developing device of the image forming apparatus according to the present embodiment includes:
A stirring roller 49 as the stirring means is disposed in a circulation path of the developer 42 connecting the gear pump 48 and the developer recovery chamber 43b. As a result, the developer 42 stored in the developer tank 43 is transferred to the gear pump 4.
8, the toner circulated between the developer supply chamber 43a and the developer recovery chamber 43b and dispersed in the carrier liquid by a stirring roller 49 disposed in the circulation path, to a predetermined amount. Is stirred to a concentration of. Here, as the stirring roller 49, for example, a screw roller having spiral blades can be used.

As shown in FIG. 1, the developing solution tank 43 is formed in a closed shape except for a surface where the developing sleeve 41 is in contact with the photosensitive drum 10, as shown in FIG. The structure is such that the developer 42 in the developer tank 43 does not spill out due to the inclination or shaking of the apparatus main body. Further, in this developing device, the shape of the developing solution tank 43 can be expanded in the direction of gravity by incorporating the circulating means of the developing solution 42, so that the device main body can be made compact.

In this developing device, the developer 42
Although the gear pump 48 is shown as the circulating means, the circulating means is not limited to the gear pump 48, but may be any kind as long as it can supply the developer 42 to the coating roller 44. For example, a circulating unit having a configuration in which a piston and a -directional valve are combined may be used.

On the other hand, from the viewpoint of avoiding damage to the surface of the photosensitive drum 10, the developing sleeve 41 is preferably a flexible member. For example, the surface is wound with an elastic material such as rubber. Rolled rollers, rollers having a low elasticity member such as sponge inside, or a cylindrical belt member are conceivable. Further, as a material of the developing sleeve 41, nylon, polyimide, or the like can be used.

Here, when a cylindrical belt member is used as the developing sleeve 41, the driving method thereof becomes a problem. That is, as shown in FIGS. 4 and 5, the developing belt 2 formed of a cylindrical belt member as the developing sleeve 41 is stretched by the driving roller 3 and the driven roller 4 formed of a plurality of belt rollers. In the case of driving, as described above, in order to prevent the developing belt 2 from shifting in the axial direction, it is necessary to accurately maintain the parallelism of the rotation axes of the driving roller 3 and the driven roller 4.

For this reason, in a developing device using the developing belt 2 composed of such a cylindrical belt member, the developing belt 2 has a large number of parts in which a plurality of belt rollers are arranged. The structure for supporting the developing belt 2 and the driving means are complicated and costly, and the developing device itself is disadvantageously enlarged. In particular, in the case of an image forming apparatus provided with a color image forming apparatus having a plurality of developing devices,
There is a problem that the entire image apparatus becomes large.

Therefore, in the image forming apparatus according to the present embodiment, as shown in FIG. 2, a hollow cylindrical member is used as the developing sleeve 41, and a developing roller 41 made of the cylindrical member is provided in the hollow portion. A single drive roller 46 having a diameter smaller than the inner diameter of the developing sleeve 41 is rotatably disposed, and the drive roller 46 rotatably supports a portion of the inner peripheral surface of the developing sleeve 41. A developing device having a configuration in which a cleaning blade 47 as a pressing member is arranged in pressure contact with the outer peripheral surface of the developing roller 41 so as to apply pressure to the driving roller 46 via the developing roller 41 is used.

In the developing device having this configuration, the developing sleeve 41 is held between the driving roller 46 and the cleaning blade 47 while the driving roller 46 is
Is rotated, the developing sleeve 41 is driven and rotated by a frictional force between the developing sleeve 41 and the driving roller 46. Therefore, in this developing device, the deviation of the developing sleeve 41 can be suppressed only by maintaining the parallelism between the driving roller 46 and the cleaning blade 47, and a plurality of the developing sleeves 41 shown in FIGS. The deviation of the developing sleeve 41 can be relatively easily prevented as compared with the case where the deviation of the developing sleeve 41 is prevented by increasing the accuracy of the parallelism of the belt roller. As described above, in this developing device, the number of components of the supporting portion and the driving portion of the developing sleeve 41 can be reduced, so that simplification and cost reduction and downsizing of the developing main body can be achieved.

Here, as described above, when the developing sleeve 41 is driven by sandwiching the developing sleeve 41 between the driving roller 46 and the cleaning blade 47, the cleaning blade 47 The developer remaining on the surface can be almost completely scraped off, and the rotation of the developing sleeve 41 is not stopped or the rotation speed of the developing sleeve 41 is not reduced at the time of scraping the developer. As described above, it is necessary to press the developing sleeve 41 against the outer peripheral surface. The driving roller 46
Is pressed against the inner peripheral surface of the developing sleeve 41 so that the rotation of the developing sleeve 41 is not stopped or the rotational speed of the developing sleeve 41 is not reduced.
1 must be driven, and the peripheral speed Sa (surface speed) of the developing sleeve 41 is equal to the peripheral speed S of the photosensitive drum 10.
It is desirable that it be equal to or more than b (Sa ≧ Sb).

That is, here, the developing sleeve 41
When the peripheral speed Sa is higher than the peripheral speed Sb of the photosensitive drum 10, the amount of the developing solution pumped up by the developing sleeve 41 per unit time is relatively increased, so that the developing sleeve 41 moves onto the photosensitive drum 10. Changes such as an increase in the amount of the developer and an increase in the image density of the latent image formed on the photosensitive drum 10 occur. Such an increase in the image density of the latent image does not lead to deterioration of the image. However, when the peripheral speed Sa of the developing sleeve 41 is lower than the surface speed of the photosensitive member, the developing speed of the developing sleeve 41 per unit time is reduced. Since the pumping amount of the liquid is relatively reduced, the amount of the developer that moves on the photoconductor drum 10 is reduced, and the image density of the latent image formed on the photoconductor drum 10 is reduced. The quality of the image transferred to 84 deteriorates.

Accordingly, the developing roller 41 of the developing device is not slipped by the driving roller 46 so as to rotate at the same peripheral speed as that of the photosensitive drum 10 or at a peripheral speed higher than the peripheral speed. Preferably, it is driven to rotate. That is, even if a speed difference occurs between the inner peripheral surface of the developing sleeve 41 and the outer peripheral surface of the driving roller 46, the developing sleeve should be used in order to prevent a significant deterioration in image quality. The peripheral speed Sa of 41 is determined in advance.
The peripheral speed may be set to be equal to or higher than the peripheral speed Sb of the photosensitive drum 10.

In this developing device, the coefficient of friction between the end surface of the cleaning blade 47 in contact with the developing sleeve 41 and the outer peripheral surface of the developing sleeve 41 is determined by the coefficient of friction between the inner peripheral surface of the developing sleeve 41 and the driving roller 46. The developing sleeve 4 so as to have a coefficient of friction smaller than the outer peripheral surface of the developing sleeve 4.
1. The state (roughness or the like) of the contact surface of each of the drive roller 46 and the cleaning blade 47 and the mutual pressing force are set, so that the developing sleeve 41 rotates when the drive roller 46 rotates. Inner peripheral surface and drive roller 4
Assuming that the frictional force of the contact portion between the outer peripheral surface of the developing sleeve 41 and the cleaning blade 47 is Fb, the relationship between the frictional force Fa and Fb is as follows: It is preferable to be configured so that Fa> Fb.

With this configuration, slippage between the inner peripheral surface of the developing sleeve 41 and the outer peripheral surface of the driving roller 46 during the rotation of the driving roller 46 is eliminated, and the photosensitive drum by the developing sleeve 41 is eliminated. The developer 42 can be reliably supplied to the drum 10.

Here, an example has been described in which a cleaning blade 47 for scraping off the developer on the developing sleeve 41 is used as a pressing means for pressing the developing sleeve 41 against the driving roller 46. The pressing means is not limited to this as long as it satisfies the frictional force relationship.For example, an opposing roller disposed at a position opposing the drive roller 46 with the developing sleeve 41 interposed therebetween may be used. It is also possible to use it as a pressing means. However, as described above, by also using the cleaning blade 47 as the pressing means, a developing device having a more compact and inexpensive configuration can be realized.

In order to drive the developing sleeve 41 with less delay by the cleaning blade 47 and the driving roller 46, as shown in FIG. 3, an inner peripheral surface of the developing sleeve 41 is covered with a rubber layer or the like. High friction member layer 4
1a may be provided.

[0044]

According to the first to sixth aspects of the present invention,
Since the developing device can be configured with a small number of parts, simplification and cost reduction of the support structure and the driving means of the developer carrier,
Further, it is possible to reduce the size of the developing device, and even in an image forming device having a plurality of developing devices, such as a color image forming device, an excellent effect that the size of the entire device can be reduced and the cost can be reduced. There is.

In particular, according to the invention of claim 2, there is an excellent effect that the liquid developer can be more uniformly applied to the developer carrier even with a small number of members.

According to the third aspect of the present invention, the frictional force Fa at the contact portion between the inner peripheral surface of the developer carrier and the outer peripheral surface of the drive roller is equal to the outer peripheral surface of the developer carrier. Since the frictional force Fb of the contact portion with the pressing member is set to be larger, the slip between the inner peripheral surface of the developer carrier and the outer peripheral surface of the driving roller during rotation of the driving roller can be eliminated. There is an excellent effect that the developer can be reliably supplied to the latent image carrier by the developer carrier.

According to the fourth aspect of the present invention, the high friction member layer is provided on the inner peripheral surface of the developer carrier which is driven to rotate in contact with the drive roller. The inner peripheral surface of the developer carrier and the outer peripheral surface of the driving roller can be made more difficult to slip when the driving roller rotates,
There is an excellent effect that the developer carrier can more reliably supply the developer to the latent image carrier.

According to the fifth aspect of the present invention, the peripheral speed Sa of the developer carrier at the time of rotation of the drive roller is set to be higher than the peripheral speed Sb of the latent image carrier. The shortage of the supply amount of the developer per unit time supplied to the latent image carrier by the developer carrier can be solved, and the decrease of the image density due to the shortage of the supply amount of the developer can be prevented. Has an excellent effect.

According to the sixth aspect of the present invention, since the pressing member is constituted by the cleaning blade for scraping the liquid developer formed on the peripheral surface of the developer carrier, the pressing member is There is an excellent effect that the body driving means can be configured more compactly and at lower cost.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus according to an embodiment.

FIG. 2 is a cross-sectional view illustrating a schematic configuration of a main part of a developing device in the image forming apparatus according to the embodiment.

FIG. 3 is a cross-sectional view illustrating another schematic configuration of a main part of a developing device in the image forming apparatus according to the embodiment.

FIG. 4 is a cross-sectional view illustrating a schematic configuration of a developing device in a conventional image forming apparatus.

FIG. 5 is a cross-sectional view illustrating another schematic configuration of a developing device in a conventional image forming apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 photoconductor drum 20 charging roller 30 exposing device 40 developing device 41 developing sleeve 41 a high friction member 42 developing solution 43 developing solution tank 44 application roller 45 metering blade 46 driving roller 47 cleaning blade 48 gear pump 49 stirring roller 50 transfer roller 60 cleaning Device 70 Static eliminator 80 Paper feeder 84 Transfer paper 90 Fixing device

Claims (6)

[Claims] A liquid developer layer in which a toner is dispersed in a dielectric carrier liquid is formed on a developer carrier, and a liquid on the developer carrier is formed on a latent image carrier on which an electrostatic latent image is formed. An image forming apparatus for developing an electrostatic latent image on a latent image carrier by bringing a developer into contact with the developer, the developer carrier comprising a hollow cylindrical member, and a rotatable inside the hollow portion of the developer carrier. A driving roller for rotatably driving the developer carrying member disposed on the pressing member, and a pressing member disposed in pressure contact with an outer peripheral surface of the developer carrying member so as to apply pressure to the driving roller via the developer carrying member. An image forming apparatus comprising: 2. The image forming apparatus according to claim 1, further comprising an application roller for applying the liquid developer to an outer peripheral surface of the developer carrier. 3. The image forming apparatus according to claim 1, wherein a frictional force of a contact portion between an inner peripheral surface of the developer carrier and an outer peripheral surface of the driving roller when the driving roller rotates is F.
a, wherein the relationship between the frictional forces Fa and Fb is Fa> Fb, where Fb is the frictional force at the contact portion between the outer peripheral surface of the developer carrier and the pressing member. apparatus. 4. The image forming apparatus according to claim 1, 2 or 3, wherein a high friction member layer is provided on an inner peripheral surface of the developer carrier which is rotated and driven in contact with the drive roller. An image forming apparatus, comprising: 5. The image forming apparatus according to claim 1, wherein the peripheral speed of the developer carrying member is Sa and the peripheral speed of the latent image carrying member is Sb when the driving roller rotates. When
An image forming apparatus, wherein the relationship between the peripheral speeds Sa and Sb is Sa ≧ Sb. 6. The image forming apparatus according to claim 1, wherein the pressing member is a cleaning blade for scraping a liquid developer supplied to a peripheral surface of the developer carrier. An image forming apparatus, comprising: