JP2001296748A - Wet image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wet image forming device where visible image density is easily and inexpensively made an intended density by regulating the layer thickness of liquid developer on a coating roller carrying the liquid developer applied to a developing roller to a desired layer thickness. SOLUTION: A flexible metering blade 16a functioning as a layer thickness regulating member is arranged to have specified bite amount on the surface of the coating roller 14. Thus, the passing amount of the liquid developer 10 drawn up to the surface of the coating roller 14 is regulated at an abutting part between the metering blade and the roller 14 and the uniform liquid developer layer having the desired layer thickness is obtained. The liquid developer is transferred to the developing roller side at an opposed part to the developing roller 12 at the transfer rate of about 100%, and used to make a latent image visible in a developing area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a wet image forming apparatus such as a facsimile, a printer, and a copying machine.

[0002]

2. Description of the Related Art Conventionally, as a wet image forming apparatus, an apparatus which forms an electrostatic latent image on a surface of a photoreceptor as an image carrier and visualizes the latent image with a liquid developer supplied by a developer carrier is known. Various proposals have been made. In this type of wet image forming apparatus, the surface of a photoreceptor is uniformly charged by a charging unit, and the surface of the photoreceptor is exposed by a writing unit in accordance with image data to form an electrostatic latent image.

As the developer carrying member, a developing device using a developing roller or a developing belt has been proposed. The developer carrier carries and transports a thin layer of the liquid developer in a portion facing the photoconductor as a latent image carrier, and transfers the liquid developer to an image portion of a latent image formed on the photoconductor. The development is performed. As the liquid developer, a liquid developer in which toner is dispersed in a liquid is used, and is usually stored in a developer storage section.

In this wet image forming apparatus, it is necessary to form a uniform thin liquid developer layer of the liquid developer on the developing roller or the developing belt (hereinafter referred to as a developing roller). It is conceivable to provide a developer applying member. As the developer applying member, it has been considered to use a roller-shaped application roller which is also used for ink application of a printing press. In this method, the liquid developer pumped onto the application roller is carried and conveyed to a portion facing the surface of the developing roller, and is transferred to the surface of the developing roller. Further, as a modified example thereof, a belt-shaped coating belt, a hollow cylindrical coating sleeve, or the like can be considered.

In the above wet image forming apparatus,
The thin layer of the liquid developer formed on the surface of the developing roller develops the electrostatic latent image on the photoreceptor in a developing area to form a visible image. At this time, the residual liquid developer remaining on the developing roller and the like that has passed through the developing area is removed by the scraping blade and collected in the developer storage tank. Then, the toner image formed on the photoreceptor is transferred to a transfer paper and fixed by a fixing unit to form an image. After the transfer step, the transfer residual developer remaining on the photoreceptor is removed by the cleaning unit, and the image forming step is completed.

In the wet image forming apparatus having the above structure,
The visible image density is determined by the liquid developer carrying amount per unit area of the liquid developer supplied from the developing roller and formed on the photoreceptor surface. For this reason, it is required to precisely regulate the amount of the liquid developer carried on the surface of the developing roller. In particular, in the case of constant speed development in which the surface of the developing roller and the surface of the photoreceptor move at a constant speed, the visible image density is determined by the amount of liquid developer carried per unit area on the surface of the developing roller. There is a need to precisely regulate the amount of developer carried.

Conventionally, as a method of forming a liquid developer layer on an application roller or the like as a developer applying member, there is a method of directly immersing the application roller or the like in a liquid developer in a developer accommodating portion.
This method can stably supply the liquid developer to the coating roller and the like, and has a simple mechanism, so that it is useful for reducing the size of the apparatus. Then, a developer amount regulating roller for regulating the amount of the developer is provided on the developing roller coated with the liquid developer in order to make the amount of the liquid developer carried per unit area of the developing roller surface an intended amount. A method has been proposed. This is to set the amount of liquid developer carried on the surface of the developing roller to an intended amount by the pressing force of the developer amount regulating roller. Further, there has been proposed a device in which a pressing force for pressing the application roller toward the development roller is controlled at a contact portion between the application roller and the development roller.

[0008]

However, according to the configuration using the developer amount regulating roller, it is difficult to bring the developer amount regulating roller into contact with the developing roller surface with a uniform pressing force in the axial direction of the developing roller. Thus, the amount of liquid developer carried in the axial direction was difficult to be uniform. Further, since a pressing mechanism, a driving mechanism, and the like for the developer amount regulating roller are provided, the apparatus configuration becomes complicated and costs increase. Further, in the configuration in which the pressing force of the application roller against the developing roller is controlled, there is a possibility that the configuration of the device for changing the pressing force becomes complicated or the cost increases.

Therefore, it is desired to propose another configuration for making the visible image density the intended density.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a wet image forming apparatus capable of easily and at low cost making a visible image density the intended density. It is to be.

[0011]

According to another aspect of the present invention, there is provided a wet image forming apparatus comprising: a latent image carrier having an electrostatic latent image on its surface; and a liquid developer on the surface. A developer carrier, and contacting the latent image on the surface of the latent image carrier with a thin layer of the liquid developer on the developer carrier to visualize the latent image with toner in the liquid developer. In a wet image forming apparatus for forming an image, a liquid developer is carried on the surface, and the liquid developer carried on the surface is transferred to the surface of the developer carrier at a portion facing the surface of the developer carrier. A developer applying member for forming a thin layer of liquid developer on the surface of the developer carrying member, and the amount of the liquid developer carried on the surface of the developer applying member is configured to be variable. is there.

FIG. 3 shows a state in which an application roller as a developer application member and a development roller as a developer carrier are disposed in contact with each other, and at the same time, the application roller and the development roller are driven to rotate so that the liquid developer on the application roller is rotated. 6 is a graph showing a result of measuring a ratio (hereinafter referred to as a transfer ratio) T [%] of an amount of liquid developer transferred to a developer roller side. In measuring the transfer rate T [%], both the coating roller and the developing roller have an outer diameter of 20 mm, and as shown in FIG.
The coating roller 14 is provided with a blade 16a for regulating the amount of the liquid developer carried on the surface. A blade 15 in contact with the developing roller 12 in FIG. 2 is a cleaning blade 15 for cleaning the residual developer from the surface of the developing roller after the development is completed. The measurement was performed by changing the amount of penetration of the blade 16a into the application roller 14, the thickness of the blade 16a, the linear velocity of the developing roller 12, the linear velocity of the application roller 14, and the like in several ways. Even when changed, the transition rates were almost equal (in this measurement, almost 100%).
%).

[0013] In the wet image forming apparatus of the first aspect,
Since the liquid developer carried on the surface of the developer applying member always transfers to the developer carrier at a substantially equal transfer rate,
The amount of liquid developer carried on the surface of the developer applying member determines the amount of liquid developer carried on the surface of the developer carrying member. In the present invention, since the amount of the liquid developer carried on the surface of the developer applying member is made variable, the amount of the liquid developer carried on the surface of the developer applying member is changed according to the density of the visible image to be formed. By transferring the liquid developer, the amount of the liquid developer carried on the surface of the developer carrier can be changed. This makes it possible to easily set the amount of liquid developer carried on the developer carrying member to the intended amount.

According to a second aspect of the present invention, there is provided a wet image forming apparatus according to the first aspect, wherein the liquid developer carried on the surface of the developer applying member is the same as that of the first embodiment. It is characterized in that the amount of the agent is made variable.

According to a second aspect of the present invention, there is provided a wet image forming apparatus comprising:
Since the amount of liquid developer carried on the surface of the developer applying member is made variable without changing the developer applying member, the amount of the liquid developer carried on the surface of the developer applying member is smaller than when the developer applying member is replaced. It is easy to change the amount. This makes it possible to more easily set the liquid developer carrying amount on the developer carrying member to the intended carrying amount.

According to a third aspect of the present invention, there is provided a wet image forming apparatus comprising: a latent image carrier for carrying an electrostatic latent image on the surface; and a developer carrier for carrying a liquid developer on the surface. In a wet image forming apparatus, a latent image on the surface of a carrier is brought into contact with a thin layer of a liquid developer on the developer carrier to visualize the latent image with toner in the liquid developer. The developer is carried, and the liquid developer carried on the surface is transferred to the surface of the developer carrier at a portion opposed to the surface of the developer carrier, whereby the liquid developer is transferred to the surface of the developer carrier. It has a developer applying member for forming a thin layer, and a linear velocity difference between the surface of the developer applying member and the surface of the developer carrying member is configured to be variable.

According to a third aspect of the present invention, there is provided a wet image forming apparatus comprising:
A developer application member for applying the liquid developer,
The difference between the linear velocity and the developer carrying member on the other side is variously changed. FIG.
Is the linear velocity of the developing roller 12 [mm /
s], the liquid current per unit area of the developing roller surface
Image agent loading [mg / cm²FIG. Ma in the figure
◇ indicates that the thickness of the blade 16a is 0.1 [mm].
0.15 [mm], ○ is 0.2 [mm] (hereinafter referred to as
No. S, M, L)
The linear velocity of the application roller 14 is 100 [mm / s].
Is 120 [mm / s] (hereinafter, symbols r and f, respectively)
). The symbol in the figure is blade 1
6a and thickness of coating roller 14
It was done. From the results of FIG.
When the linear velocity of the developing roller 12 is increased with the
Of liquid developer on the surface of the roller 12 [mg / cm²Is up to you
It can be seen that it decreases. Also, the developing roller 12 line
Speed is fixed and the thickness of the blade 16a is equal.
14 Two results that differ only in linear velocity (symbol r or f in the figure)
(For example, Sf and Sr)
The higher the linear velocity, the more the liquid developer on the surface of the developing roller 12
Capacity [mg / cm²] Is increasing. The above results
The difference in linear velocity between the surface of the developer applying member and the surface of the developer carrier.
Easy to change the surface of the developer carrier
Liquid developer carrying amount [mg / cm ²] To the intended amount
It becomes possible. Also, the developer carrying member transfers the developer.
Since the transfer rate to the carrier is always constant, the developer
Amount of liquid developer carried on the surface [mg / cm²] Is different
In this case, the linear velocity difference can be set according to the case.
Thus, the final amount of developer carried on the surface of the developer carrier [m
g / cm²] Can be the same or different
It works.

According to a fourth aspect of the present invention, there is provided a wet image forming apparatus.
Alternatively, in the wet image forming apparatus according to the third aspect, the amount of liquid developer that is provided opposite to the surface of the developer applying member and conveyed while being carried on the surface of the developer applying member is set to be opposite to the developer applying member. It has a developer regulating blade which regulates the amount of liquid developer carried on the surface of the developer applying member by regulating the position.

Here, conventionally, the amount of liquid developer carried per unit area [m
g / cm ² ], it is considered to use an application roller composed of a gravure roller having an engraved surface and irregularities formed thereon. The excess amount of the liquid developer supplied to the surface of the gravure roller is removed by the blade and the engraved portion on the surface of the application roller, and the amount of the liquid developer [mg / cm ² ] on the surface of the application roller can be accurately measured. Things. However, in the gravure roller, the amount of liquid developer that can be carried by one roller is determined by the unevenness formed on the surface portion. For this reason, when it is desired to change the amount to be carried, the application roller must be replaced, which is costly and troublesome.

According to a fourth aspect of the invention, there is provided a wet image forming apparatus comprising:
With the developer regulating blade, the layer thickness of the liquid developer on the developer applying member can be regulated to an intended layer thickness,
When the layer thickness is changed, it is possible to reduce costs and labor such as replacing the developer applying member.

According to a fifth aspect of the present invention, there is provided a wet image forming apparatus.
In the wet image forming apparatus, the developer regulating blade is provided in contact with the developer applying member, and the liquid developer passes through by the contact pressure between the developer applying member and the developer regulating blade. The amount of the developer is regulated, and the contact pressure of the developer regulating blade with respect to the developer applying member is configured to be variable.

[0022] In the wet image forming apparatus of the fifth aspect,
By changing the contact pressure of the developer regulating blade against the developer applying member, of the liquid developer carried and conveyed on the surface of the developer applying member, a liquid developer which can pass through a position facing the developer regulating blade Is regulated to a desired amount.
Thereby, the layer thickness of the liquid developer on the developer applying member is regulated to an intended layer thickness.

According to a sixth aspect of the present invention, there is provided a wet image forming apparatus.
Wherein the developer regulating blade comprises a flexible blade, a plurality of developer regulating blades having different thicknesses, and one of the plurality of developer regulating blades is provided with the developer applying blade. Blade holding means for holding the blade in contact with the member, wherein the developer regulating blade held by the blade holding means is selectively replaceable from among the plurality of developer regulating blades. Things.

According to a sixth aspect of the present invention, there is provided a wet image forming apparatus.
By changing the developer regulating blade held by the blade holding means, the thickness of the flexible developer regulating blade can be easily changed. by this,
The contact pressure changes depending on the thickness of the blade, and the amount of developer passing through the contact position also changes. FIG. 5 shows a case where a flexible developer regulating blade is brought into contact with an application roller 14 as a developer applying member, and four types of blades having different thicknesses are used. Amount of liquid developer carried on the surface [mg / cm ² ]
FIG. 4 is a diagram showing the results of measuring the values of. Srr connecting the mark ◇ in the figure with a dotted line is a linear velocity 147 of the developing roller 12.
[mm / s], the linear velocity of the application roller 14 is 100 [mm / s],
The Srf connecting the marks で with a solid line is a linear velocity of the developing roller 12 of 147 [mm / s] and a linear velocity of the coating roller 14 of 120 mm / s.
[mm / s], Sfr connecting the mark で with a dotted line are 290 [mm / s] linear speed of the developing roller 12, 100 [mm / s] of the coating roller 14, and Sfr connecting the mark で with a solid line.
f is the result when the linear velocity of the developing roller 12 is 290 [mm / s] and the linear velocity of the application roller 14 is 120 [mm / s].
From the results shown in this figure, the thickness of the metering blade 16a and the amount of the liquid developer carried on the developing roller 12 [mg / cm
² ], the relationship is almost inversely proportional. If the material of the blade is the same, the thicker the blade, the smaller the amount of developer carried on the developing roller surface [mg / cm ² ]; I understood. This is because, as the thickness of the metering blade 16a is smaller, the blade is more likely to bend, so that the contact pressure is reduced and the force for regulating the amount of liquid developer passing on the application roller [mg / cm ² ] is weaker. It is thought to be. Therefore, it is effective to change the thickness of the flexible blade to be brought into contact with the surface of the developer applying member in order to bring the amount of liquid developer carried on the surface of the developer carrier to the intended amount. With the simple configuration of changing the thickness, the amount of liquid developer carried on the surface of the developer carrier can be set to the intended amount.

According to a seventh aspect of the present invention, in the wet image forming apparatus of the first, second, third, fourth, fifth or sixth aspect, the linear velocity of the surface of the developer applying member is made variable. It is a feature.

[0026] In the wet image forming apparatus according to claim 7,
By changing the linear speed of the developer applying member, the linear speed difference between the surface of the developer applying member and the surface of the developer carrier is changed, and the amount of liquid developer carried on the surface of the developer carrier [mg / c]
m ² ] to the intended amount. Here, since the developer carrying member is located at a position facing the latent image carrying member and is directly involved in visualizing the latent image, when the linear velocity is changed, unexpected development to the developing region is performed. Although the influence is concerned, the developer applying member does not directly affect the developing area. Therefore, the final amount of the developer carried on the surface of the developer carrying member can be set to an intended amount without causing an unexpected influence on the developing region.

[0027] The wet image forming apparatus according to claim 8 is the seventh embodiment.
In the wet image forming apparatus, liquid development is performed such that the surface of the developer applying member is immersed at the upstream side of the developer applying member surface moving direction in the opposing portion between the surface of the developer applying member and the surface of the developer carrier. A liquid developer accommodating portion for holding the developer is provided.

[0028] In the wet image forming apparatus of claim 8,
The surface of the developer applying member immersed in the liquid developer is a liquid developer
Pump and carry it, and move
To the portion facing the developer carrier. And now
By changing the linear velocity of the image applying member, the developer is applied.
The amount of the liquid developer pumped on the member surface is changed. FIG.
Is the linear velocity [m of the application roller 14 as a developer application member.
m / s] (assuming the linear velocity of the application roller [mm / s])
Of the liquid developer per unit area of the surface of the application roller 14
Capacity [mg / cm²] (Load on the application roller [mg / cm
²FIG. Of these, the application roller
The overload is determined by the device during the actual printing sequence.
And stop it within a certain area on the surface of the application roller.
The mass of the liquid developer [mg]²Divided by
It is the value obtained by Mark ◇ in the figure is the blade thickness
Only 0.1 [mm], Δ is 0.15 [mm], ○ is 0.2
[mm] (represented by symbols S, M and L, respectively)
The white mark is a linear velocity of the developing roller 12 of 147 [mm].
/ S], the black mark is a linear velocity of 290 [mm / s] (it
(Respectively, symbols r and f). Results of FIG.
Fix the linear speed of the developing roller and increase the linear speed of the coating roller
The total amount of liquid developer carried on the application roller surface [mg
/ Cm²] Is a constant rate of change, roughly proportional to
It can be seen that the number increases with the shift. Also, the coating roller linear speed
And the thickness of the blade are fixed.
Compare two results (eg, Sf and Sr)
And the total amount of liquid developer carried on the surface of the application roller [mg / cm
²] Does not change. This is the application roller 1
4. The faster the linear velocity [mm / s] of 4, the more the liquid developer
Since the surface area of the cloth roller 14 becomes large,
The amount of liquid developer pumped up by the surface also increased
It is thought. Here, the developing roller 12 is a latent image carrier
Directly in order to visualize the latent image
If you want to change the linear velocity,
Although there is a concern about unexpected effects on the area,
Since there is no direct effect on development, even if the linear speed is changed, the development area
There is no effect on Therefore, the linear velocity of the developer applying member is changed.
Cause unexpected effects on the development area
The amount of liquid developer carried on the surface of the developer applying member without
Can be changed reliably, and the final
The total amount of developer carried can be set to an intended amount.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a wet electrophotographic copying machine as a wet image forming apparatus will be described below.

FIG. 1 is a schematic configuration diagram of a wet electrophotographic copying machine according to the present embodiment. A charging roller 2, an exposing device 3, a wet developing device 4, a transfer device 5, a cleaning device 6, and the like are arranged around a photosensitive drum 1 as an image carrier.

The photosensitive drum 1 is driven to rotate in the direction of the arrow a in the figure, and its surface is charged at a position facing the charging roller 2, and then irradiated with light at a position facing the exposure device 3 based on image information. To carry an electrostatic latent image. This electrostatic latent image is
When passing through the position facing the wet developing device 4, the toner as the image forming particles in the liquid developer 10 is adhered and visualized.

The liquid developer 10 used in the present embodiment has a high-concentration toner dispersed in a carrier made of an insulating liquid such as dimethylpolysiloxane oil and exhibits a high viscosity of 100 to 10000 mPa · s. Has been adjusted to be.

When a toner image as a visible image formed by toner adhesion on the photosensitive drum 1 passes through a transfer nip portion, which is a position facing the transfer device 5, the toner image is supplied from the sheet feeding portion 7 at an appropriate timing. The image is transferred onto a transfer sheet P as a material to be transferred which has been conveyed to the transfer nip portion. The transfer paper P on which the toner image has been transferred in this way is sent to the fixing device 8, and
The toner image is fixed under the action of heat and pressure.

By repeating the above steps, toner images are sequentially formed on a plurality of transfer papers P.

Next, the structure of the wet developing device 4 will be described. The wet developing device 4 has a developer storage tank 19 that stores the liquid developer 10. This developer storage tank 1
9, a developing roller 12 as a developer carrier,
Coating roller 14 and developing roller 1 as developer applying members
Cleaning member 1 consisting of a cleaning blade for cleaning the liquid developer 10 on the substrate 2 and a supporting portion thereof
5, a circulation pump 17 for circulating the liquid developer 10, a stirring screw 18a, 18b for stirring the liquid developer 10, and the like are provided. Developing roller 12 and coating roller 14
Both have an outer diameter of 20 mm, the surface layer of the developing roller is made of rubber, and the application roller 14 is made of metal SUS.

The application roller 14 is rotated while a part of the application roller 14 is immersed in the liquid developer 10 in the developer accommodating tank 19, so that the liquid developer 10 adheres to the surface and is pumped up. When the liquid developer 10 passes through the contact portion with the developing roller 12 that is driven to rotate, the collected liquid developer 10 is transferred to the developing roller 12 side, and
(2) A liquid developer thin film is formed on the surface.

The developing roller 12, which is rotationally driven in the direction of the arrow b in the figure by drive means (not shown), has a part thereof protruding from an opening provided in the developer accommodating tank 19, The nip portion is formed by abutting. In the nip portion, the photosensitive drum 1
The surface moves in the same direction as. The liquid developer 10 applied to the developing roller 12 by the applying roller 14 becomes a thin layer of the liquid developer thin layer and is sandwiched between the nip portions. Further, a developing bias as a voltage is applied to the developing roller 12 by an electric field forming means (not shown), and the nip portion is a developing nip portion where a developing electric field is formed. The developing electric field causes an electrostatic force to act on the toner in the thin liquid developer layer passing through the nip portion with the rotation of the developing roller 12, and causes the toner at the position facing the electrostatic latent image to move to the carrier. At the same time, the image is transferred from the developing roller 12 to the image portion of the electrostatic latent image on the photosensitive drum 1. Further, the toner at a position facing the non-image portion of the photosensitive drum 1 is moved toward the surface of the developing roller 12.
For this reason, only a small amount of carrier is transferred to the non-image portion of the photosensitive drum 1 without toner being attached.

In this embodiment, the transfer paper P
The configuration is such that the density of the toner image obtained above can be easily and reliably set to the intended density. Hereinafter, a configuration which is a feature of the present embodiment will be described.

FIG. 2 shows that the developing roller 1 is moved from the coating roller 14 to the developing roller 1.
FIG. 2 is a partially enlarged view showing a structure for applying a liquid developer to an image forming apparatus 2; The liquid developer 1 in the rotation direction of the coating roller 14
A developer regulating blade that regulates the layer thickness of the liquid developer 10 on the application roller 14 is provided on the surface of the application roller 14 at the downstream side where the liquid developer 10 is drawn and at the upstream side passing through the contact portion with the development roller 12. Is provided. The metering blade 16a is held by a holding plate 16b and a spacer 16c as blade holding means. The metaling blade 16a is a flexible blade made of a thin metal (SUS) plate, and is arranged so as to have a predetermined penetration amount. The digging amount is a numerical value of a theoretical digging amount that would be stuck in the application roller 14 if the metering blade 16a was not bent. Thus, the metering blade 16a is actually pressed against the surface of the application roller 14 with a predetermined contact pressure.

The metering blade 16a is detachable from a support portion formed by the holding plate 16b and the spacer 16c, and one of a plurality of types of metering blades 16a having different thicknesses has an appropriate thickness. One can be selected and mounted. Then, the metering blade 16a having an intended thickness can be replaced as needed. And the application roller 14
The liquid developer 10 pumped by the
The layer thickness is uniformly regulated by the contact pressure when passing through the contact portion between the metal blade 4 and the metering blade 16a.

Here, of the liquid developer 10 carried on the application roller 14, the transfer rate T of the liquid developer 10 that transfers from the portion facing the developing roller 12 to the developing roller 12 is shown in FIG. It has been found to be almost 100% as shown. The transfer rate is hardly influenced by the amount of the metering blade 16a biting into the applying roller 14, the thickness of the metering blade 16a, the developing roller linear speed, the applying roller linear speed, and the like.

FIG. 5 shows the result of examining the relationship between the thickness of the metering blade 16a and the carrying amount [mg / cm ² ] of the liquid developer 10 formed on the developing roller 12 in the above configuration. FIG. As described above, this figure shows that the thicker the metering blade 16a, the smaller the amount of developer carried on the surface of the developing roller, and the smaller the thickness, the greater the amount. This means that the smaller the thickness of the metering blade 16a is, the more the liquid developer carried on the application roller 14 [mg
/ Cm ² ], the larger the thickness, the smaller the
This is considered to be the result of almost 100% transfer of the developer on the developing roller 12 to the developing roller 12. Therefore, the metering blade 16a
By setting the thickness of the developing roller to an intended thickness, the amount of the liquid developer carried on the surface of the developing roller can be made an intended amount.

Further, in the present embodiment, the linear velocity [mm / s] of the application roller 14 is configured to be variable. Each of the coating roller 14 and the developing roller 12 is provided with a coating gear or a developing gear on a shaft portion, and each gear is driven to rotate by a driving gear. In particular, a plurality of application gears having different diameters are provided on the application roller shaft,
The application gear meshing with a drive gear (not shown) of the drive device can be switched by a gear switching means (not shown). Various configurations are conceivable for the configuration in which the linear velocity [mm / s] of the application roller is variable, such as using a motor having a variable rotation speed in addition to the configuration described above. Further, the developing roller 12
Are driven to rotate at a linear speed equal to that of the photosensitive drum 1 by a driving device (not shown). As already described with reference to FIG. 6, the linear velocity [mm / s] of the application roller has a correlation with the amount of liquid developer carried on the surface of the application roller [mg / cm ² ], and the linear velocity [mm / s] The faster the speed, the greater the amount of liquid developer applied to the surface of the application roller, that is, the amount of liquid developer 10 pumped up for a certain period of time. When the developing roller linear velocity [mm / s] is constant, the coating roller linear velocity [mm / s]
s], the application roller 14 and the developing roller 12
Will change. As already described with reference to FIG. 4, when the linear velocity of the developing roller is constant, as the linear velocity [mm / s] of the application roller 14 increases, the amount of developer carried on the surface of the development roller increases, and Linear velocity [m
m / s], the developer carrying amount on the developing roller surface decreases. From these facts, also in the present embodiment, by setting the linear velocity [mm / s] of the application roller 14 to the intended linear velocity [mm / s], the pumping amount of the liquid developer 10 to the application roller 14 can be reduced. Along with the change, the thickness of the liquid developer layer on the surface of the developing roller when the liquid developer 10 pumped and carried on the surface is transferred to the surface of the developing roller by the linear velocity difference between the application roller 14 and the developing roller 12 is changed. be able to.

Therefore, the thickness of the flexible metering blade 16a to be brought into contact with the surface of the developer applying member may be changed in order to bring the amount of liquid developer carried on the surface of the developer carrier to the intended amount. Effective, metering blade 1
6a, the developing roller 1 can be easily changed in thickness.
The amount of liquid developer carried on the two surfaces can be reliably maintained at the intended amount.

According to the above-described embodiment, by setting the thickness of the metering blade 16a, the linear velocity [mm / s] of the coating roller, and the like according to the situation, it is possible to carry the intended liquid developer on the surface of the developing roller 12. And thus the desired image density. Therefore, unlike the case where a gravure roller is used as the application roller 14, it is not necessary to replace the entire application roller 14 in order to change the image density, and the labor and time required for replacement can be reduced. In addition, by increasing the thickness of the metering blade 16a and / or the linear velocity [mm / s] of the application roller 14, the image density can be adjusted in small increments, and the intended image density can be adjusted. Can be obtained more accurately.

In this embodiment, the photosensitive layer on the surface of the photosensitive drum 1 is made of amorphous silicon (a-S
i) is used. This can reduce damage to the surface of the photosensitive drum 1 due to contact with the developing roller 12 and deterioration of the surface due to water absorption and swelling, thereby extending the life of the latent image carrier. it can. Further, since the relative dielectric constant of the photosensitive layer can be increased, the developing electric field can be increased, and a good image can be obtained.

Further, in the above-described embodiment, a roller-shaped developer applying member and a developer carrying member have been described. However, the present invention can be applied to any structure capable of carrying a liquid developer on the surface. . Therefore, for example, the present invention can be applied to belt-shaped ones such as a developer application belt and a development belt.

[0048]

According to the first aspect of the present invention, there is provided a wet image forming apparatus.
Since the liquid developer carrying amount on the developer carrying member can be easily adjusted to the intended carrying amount, there is no need to change the pressing force or replace the application roller, and the intended amount can be easily and at low cost. There is an excellent effect that a visible image density can be obtained.

According to the wet image forming apparatus of the second aspect, the amount of liquid developer to be carried on the developer carrying member can be more easily adjusted to the intended amount, so that the intended amount can be achieved more easily and at lower cost. There is an excellent effect that a visible image density can be obtained.

According to the third aspect of the present invention, there is no need to change the pressing force or replace the application roller, and the intended visible image density can be obtained easily and at low cost. Has an excellent effect.

According to the wet image forming apparatus of the fourth aspect, the cost and labor when changing the layer thickness of the liquid developer on the developer applying member can be reduced, so that the intention can be easily and at low cost. There is an excellent effect that a visual image density can be obtained. Further, according to the present invention, it is possible to use a roller having a smooth surface as a developer applying member, so that there is no need to clean foreign matters adhered to a concave portion as in the case of using a gravure roller. There is also an excellent effect that the cost and labor can be further reduced. Further, there is an excellent effect that the cost required for forming a roller having an uneven surface can be reduced.

According to the wet image forming apparatus of the present invention, the intended visible image density can be obtained with an easy configuration in which the contact pressure of the developer regulating blade against the developer applying member can be changed. Has an effect.

According to the wet image forming apparatus of the present invention, the amount of the liquid developer carried on the surface of the developer carrier can be easily adjusted to the intended amount, so that the intended visible image density can be easily obtained. There is an excellent effect that you can.

According to the wet image forming apparatus of the present invention, the liquid developer carried on the surface of the developer carrying member is constituted by variably changing the linear velocity between the surface of the developer applying member and the surface of the developer carrying member. In an embodiment in which the amount is set to an intended amount, there is an excellent effect that an intended visible image density can be easily obtained without causing an unexpected influence on a development area.

According to the wet image forming apparatus of the eighth aspect, the amount of the liquid developer carried on the surface of the developer applying member can be changed without causing an unexpected influence on the developing area. effective.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a main part of a wet image forming apparatus according to an embodiment.

FIG. 2 is a partially enlarged view showing a structure for applying a liquid developer from a coating roller to a developing roller.

FIG. 3 is a diagram showing a measurement result of a transfer rate T of a liquid developer from a coating roller to a developing roller.

FIG. 4 is a diagram showing a liquid developer carrying amount [mg / cm ² ] on a developing roller with respect to a developing roller linear velocity [mm / s].

FIG. 5 is a diagram showing the relationship between the thickness of a metering blade and the amount of liquid developer carried on a developing roller [mg / cm ² ].

FIG. 6 is a diagram showing the total amount of liquid developer carried on the application roller [mg / cm ² ] with respect to the linear velocity [mm / s] of the application roller.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photoconductor drum 2 charging roller 3 exposure device 4 wet developing device 5 transfer device 6 cleaning device 7 paper feeding unit 8 fixing device 10 liquid developer 12 developing roller 14 application roller 15 cleaning member 16 application amount regulating member 16a metering blade 18 Stirring screw 19 Developer storage tank

Claims (8)

[Claims] A latent image carrier for carrying an electrostatic latent image on a surface thereof;
A developer carrying member carrying a liquid developer on the surface thereof, and contacting a latent image on the surface of the latent image carrying member with a thin layer of the liquid developer on the developer carrying member to thereby form a liquid developer. A liquid image developer that visualizes the latent image with the toner of claim 1, wherein a liquid developer is carried on the surface, and the liquid developer carried on the surface is developed at a portion facing the developer carrier surface. A developer applying member that forms a thin layer of liquid developer on the surface of the developer carrying member by transferring to the surface of the developer carrying member, and variably controls the amount of the liquid developer carried on the surface of the developer applying member. A wet image forming apparatus. 2. The wet image forming apparatus according to claim 1, wherein the amount of liquid developer carried on the surface of the same developer applying member is variable in the same developer applying member. . 3. A latent image carrier for carrying an electrostatic latent image on a surface thereof;
A developer carrying member carrying a liquid developer on the surface thereof, and contacting a latent image on the surface of the latent image carrying member with a thin layer of the liquid developer on the developer carrying member to thereby form a liquid developer. A liquid image developer that visualizes the latent image with the toner of claim 1, wherein a liquid developer is carried on the surface, and the liquid developer carried on the surface is developed at a portion facing the developer carrier surface. A developer applying member for forming a thin layer of liquid developer on the surface of the developer carrier by transferring the developer to the surface of the developer carrier, and a linear velocity between the surface of the developer applying member and the surface of the developer carrier. A wet image forming apparatus, wherein the difference is configured to be variable. 4. The wet image forming apparatus according to claim 2, wherein the amount of the liquid developer provided to face the developer applying member and conveyed while being carried on the developer applying member is controlled. A wet image forming apparatus comprising: a developer regulating blade that regulates an amount of a liquid developer carried on a surface of the developer applying member by regulating the position at a position facing the developer applying member. 5. A wet image forming apparatus according to claim 4, wherein said developer regulating blade is provided in contact with said developer applying member, and said developer regulating member is in contact with said developer regulating blade. A wet-type image forming apparatus wherein the amount of passage of the liquid developer is regulated by pressure, and a contact pressure of the developer regulating blade to the developer applying member is made variable. 6. The wet image forming apparatus according to claim 5, wherein the developer regulating blade comprises a flexible blade,
A plurality of developer regulating blades having different thicknesses; and blade holding means for holding one of the plurality of developer regulating blades in contact with the developer applying member. A wet image forming apparatus, wherein a developer regulating blade is selectively replaceable among the plurality of developer regulating blades. 7. The wet image forming apparatus according to claim 1, wherein the linear velocity of the surface of the developer applying member is variable. 8. The wet-type image forming apparatus according to claim 7, wherein an upstream side of the developer applying member surface moving direction in a portion where the developer applying member surface and the developer carrier surface oppose each other.
An image forming apparatus, comprising: a liquid developer container for holding a liquid developer such that a surface of the developer applying member is immersed.