JP5305702B2 - Wet image forming apparatus and wet image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wet image forming apparatus and a wet image forming method for preventing filming on a photoreceptor over a long period. <P>SOLUTION: The wet image forming apparatus includes the photoreceptor, a charging device, a driving developing roller as a liquid developing device, and the wet image forming method uses the wet image forming apparatus. The image forming apparatus also includes a cleaning blade for cleaning toner remaining on the surface of the photoreceptor and a polishing device for polishing the surface of the photoreceptor. The polishing device uses a prescribed liquid polishing agent. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a wet image forming apparatus and a wet image forming method using the same, and more particularly to a wet image forming apparatus provided with a predetermined polishing apparatus and a wet image forming method using the wet image forming apparatus.

Conventionally, in a wet image forming apparatus, a liquid developing device is mounted as a developing device, and an electrostatic latent image formed on a photoreceptor is developed with a liquid developer supplied from the liquid developing device.
At this time, when the development is continuously performed, filming of the toner with respect to the photosensitive member becomes a big problem.
That is, there has been a problem that a part of the resin constituting the toner is peeled off and adheres to the surface of the photoreceptor, which causes the image characteristics to be remarkably deteriorated.
However, in the wet image forming apparatus provided with the photoreceptor, there is no suitable polishing apparatus yet, and a cleaning blade 260 used in the dry image forming apparatus 200 as shown in FIG. This is the state.
That is, in the wet image forming apparatus, although the surface of the photoconductor is partially covered with a water-insoluble solvent contained in the developer, the polishing apparatus used in the dry image forming apparatus has When the surface of the photoconductor is excessively polished with a cleaning blade or the like, there is a problem that the surface of the photoconductor is easily damaged as well as the coating of the water-insoluble solvent is easily peeled off.

On the other hand, in the dry image forming apparatus, unlike the wet image forming apparatus, there is no special feature that it is partially covered with the water-insoluble solvent contained in the developer. It has been proposed (see, for example, Patent Document 1).
More specifically, in the image forming apparatus as shown in FIG. 6, after the toner image is transferred from the photosensitive drum 301 serving as an image carrier to the recording medium 302, an abrasive containing the surface remaining on the surface of the photosensitive drum is contained. A cleaning blade 304 for removing the toner 303 is provided.
A toner retaining member 305 made of a flexible sheet for forming the section S between the cleaning drum 304 and the surface of the photosensitive drum 301 is disposed upstream of the cleaning blade 304 in the rotational direction of the photosensitive drum 301. The tip of the member and the surface of the photosensitive drum 301 are arranged so as to have a separation portion 307, and the abrasive-containing toner falling to the section portion S is temporarily retained while contacting the surface of the photosensitive drum 301. And a function of discharging the staying material from the separation unit 307 to the toner transport unit 308.

Further, in an electrophotographic apparatus having a cleaning blade for removing residual toner on the surface of the photosensitive drum, a cleaning roller having a conductive polyurethane coating film containing abrasive particles as cleaning means for assisting the cleaning blade It is proposed to further provide (see, for example, Patent Document 2).
More specifically, a conductive roller base material made of a polyurethane elastomer having a hardness of 10 to 40 and a volume resistivity of 1 × 10 ⁵ to 1 × 10 ⁹ Ω · cm is provided on the outer periphery of the roller metal core, Further, the cleaning roller has a conductive polyurethane coating film containing silica or alumina as abrasive particles formed on the outer surface thereof.

In addition, an image forming apparatus provided with a predetermined polishing means has been proposed so that image flow does not occur even when an amorphous silicon photoconductor is used (see, for example, Patent Document 3).
More specifically, as shown in FIG. 7, a charging unit 403 for applying a charge to the outer surface of the amorphous silicon photoconductor 402, an exposure unit 404 for irradiating the photoconductor with light, and an electrostatic latent image A developing unit 405 that forms a toner image on the surface of the photoreceptor, a transfer unit 408 that transfers the toner image to a transfer material, a cleaning unit 409 that removes residual toner on the surface of the photoreceptor, and a residual electrostatic latent image are removed. An image forming apparatus 401 that includes a static eliminating unit 410 and a polishing unit 412, and has a surface polishing rate per rotation of the photosensitive member 402 by the polishing unit 412 of 0.0001 to 0.05 mm / rotation. Therefore, it has been proposed to dispose polishing means 412 including abrasive particles having a Mohs hardness exceeding 11 and a particle size of # 800 or more according to the standard of JIS-R-6001.
JP 2004-348004 A (Claims etc.) Japanese Patent No. 2631935 (Claims etc.) JP 2004-126217 A (Claims etc.)

However, the cleaning means described in Patent Document 1 uses the falling phenomenon of abrasive-containing toner and cannot be applied to a liquid developer in which toner is dispersed in an insulating liquid in a wet image forming apparatus. It was observed.
Further, the polishing means disclosed in Patent Documents 2 to 3 have a problem that when used in a wet image forming apparatus, the photoconductor is excessively polished, and image characteristics are likely to deteriorate with time.
That is, as described above, in the wet image forming apparatus, if the surface of the photoreceptor is excessively polished, the coating of the water-insoluble solvent is likely to be peeled off, and the surface of the photoreceptor is easily damaged. Thus, there has been a problem that high-quality image characteristics cannot be obtained over a long period of time.

Accordingly, as a result of intensive studies, the present inventors have found that the use of a predetermined liquid abrasive in the polishing apparatus can prevent the occurrence of filming on the photoreceptor for a long period of time.
In other words, according to the present invention, the occurrence of filming is prevented over a long period of time by appropriately polishing the surface of the photoreceptor with a polishing apparatus through a predetermined liquid abrasive, thereby providing excellent image characteristics. An object of the present invention is to provide a wet image forming apparatus capable of stably obtaining the above and a wet image forming method using the same.

According to the present invention,
A photoreceptor,
A charging device for charging the photoconductor to a predetermined potential;
A developing device for supplying a liquid developer in which toner is dispersed in an insulating liquid to a photoreceptor;
A cleaning blade for cleaning the toner remaining on the surface of the photoreceptor;
A polishing apparatus for polishing the surface of the photoreceptor;
A wet image forming apparatus comprising:
In the polishing apparatus, using a liquid abrasive containing inorganic particles,
The inorganic particles are at least one selected from the group consisting of titanium oxide, aluminum oxide, and zirconium oxide,
The average particle size of the inorganic particles is a value within the range of 0.5 to 10 μm , and
A wet-type image forming apparatus, further comprising a driving device for bringing the developing device into and out of contact with the photosensitive member, wherein the developing device is separated from the photosensitive member by the driving device during cleaning by the polishing device. An apparatus is provided that can solve the problems described above.
That is, with this configuration, the surface of the photoreceptor can be appropriately polished by a polishing apparatus via a predetermined liquid abrasive.
Moreover, since the inorganic particles are contained in a predetermined solvent, the inorganic particles can be effectively prevented from scattering to the outside.
Therefore, the occurrence of filming can be prevented over a long period of time, and thereby excellent image characteristics can be stably obtained.
Further, by limiting the types of inorganic particles in this way, the polishing apparatus can polish the surface of the photoreceptor more appropriately and effectively via the liquid abrasive containing the predetermined inorganic particles.

In addition, by adopting the configuration of the drive type developing device as described above, the developing device can be separated from the photosensitive member at the time of cleaning, so that the liquid abrasive is mixed in the developing device. Can be effectively prevented.

Further, in configuring the wet image forming apparatus of the present invention, the polishing apparatus includes a polishing roller, and an abrasive supply means for supplying a liquid abrasive to the polishing roller is further provided. preferable.
By limiting the configuration of the polishing apparatus in this manner, the liquid abrasive can be reliably supplied to the polishing roller, and the polishing roller can further appropriately adjust the surface of the photoreceptor via the predetermined liquid abrasive. And it can polish effectively.

In configuring the wet image forming apparatus of the present invention, the content of the inorganic particles may be set to a value within the range of 2 to 30% by weight when the total amount of the liquid abrasive is 100% by weight. preferable.
By limiting the content of the inorganic particles in this way, the polishing apparatus can further appropriately and effectively polish the surface of the photoreceptor through a liquid abrasive containing a predetermined amount of inorganic particles.

In constituting the wet image forming apparatus of the present invention, it is preferable that the liquid abrasive contains at least one selected from the group consisting of paraffin compounds, silicone compounds, and higher fatty acid esters as a solvent.
By limiting the type of solvent in the liquid abrasive as described above, the polishing apparatus can further appropriately and appropriately apply the surface of the photoconductor via the liquid abrasive constituted by containing inorganic particles in a predetermined solvent. It can be effectively polished.

In configuring the wet image forming apparatus of the present invention, the viscosity of the liquid abrasive is preferably set to a value in the range of 10 to 150 mPa · sec (measurement temperature: 25 ° C.).
By limiting the viscosity of the liquid abrasive as described above, the polishing apparatus can polish the surface of the photoreceptor more appropriately and effectively via the liquid abrasive having a predetermined viscosity.

In configuring the wet image forming apparatus of the present invention, it is preferable that a driving device for bringing the polishing device into and out of contact with the photosensitive member is further provided.
As described above, the configuration of the drive-type polishing apparatus enables the polishing apparatus to be separated from the photosensitive member during non-cleaning, so that the liquid abrasive is mixed into the developing device. Can be effectively prevented.

Another aspect of the present invention is as follows:
A photoreceptor,
A charging device for charging the photoconductor to a predetermined potential;
A developing device for supplying a liquid developer in which toner is dispersed in an insulating liquid to a photoreceptor;
A cleaning blade for cleaning the toner remaining on the surface of the photoreceptor;
A polishing apparatus for polishing the surface of the photoreceptor;
A wet image forming method using
In the polishing apparatus, using a liquid abrasive containing inorganic particles,
The inorganic particles are at least one selected from the group consisting of titanium oxide, aluminum oxide, and zirconium oxide,
The average particle size of the inorganic particles is a value within the range of 0.5 to 10 μm , and
A wet-type image forming apparatus, further comprising a driving device for bringing the developing device into and out of contact with the photosensitive member, wherein the developing device is separated from the photosensitive member by the driving device during cleaning by the polishing device. Is the method.
That is, by carrying out in this way, the surface of the photosensitive member can be appropriately polished by a polishing apparatus through a predetermined liquid abrasive.
Moreover, since the inorganic particles are contained in a predetermined solvent, the inorganic particles can be effectively prevented from scattering to the outside.
Therefore, the occurrence of filming can be prevented over a long period of time, and thereby excellent image characteristics can be stably obtained.

In carrying out the wet image forming method of the present invention, the polishing apparatus includes a polishing roller and an abrasive supply unit, and when polishing the surface of the photoreceptor, the abrasive supply unit is used for polishing. It is preferable to supply a liquid abrasive | polishing agent with respect to a roller.
By carrying out in this way, the liquid abrasive can be reliably supplied to the polishing roller, and the polishing roller can polish the surface of the photoreceptor more appropriately and effectively via the predetermined liquid abrasive. can do.

Further, in carrying out the wet image forming method of the present invention, a driving device for bringing the polishing device into and out of contact with the photosensitive member is further provided. When the polishing device is not cleaning, the developing device is removed from the photosensitive member. It is preferable to separate them.
By carrying out in this way, it is possible to effectively prevent the liquid abrasive from entering the developing device.

[First embodiment]
The first embodiment of the present invention, as shown in FIG.
A photoreceptor 51;
A charging device 53 for charging the photoreceptor 51 to a predetermined potential;
A developing device 12 for supplying a liquid developer 11 in which toner is dispersed in an insulating liquid to the photoreceptor 51;
A cleaning blade 60 for cleaning toner remaining on the surface of the photoreceptor 51;
A polishing device 58 for polishing the surface of the photoreceptor 51;
A wet image forming apparatus 10 comprising:
In the polishing apparatus, a liquid abrasive containing inorganic particles is used, and the inorganic particles are at least one selected from the group consisting of titanium oxide, aluminum oxide, and zirconium oxide, and the average particle size of the inorganic particles is 0. A value in the range of 5-10 μm , and
A wet-type image forming apparatus, further comprising a driving device for bringing the developing device into and out of contact with the photosensitive member, wherein the developing device is separated from the photosensitive member by the driving device during cleaning by the polishing device. Device 10.

  Hereinafter, the wet image forming apparatus according to the present invention will be described in detail with reference to an example of a tandem type wet image forming apparatus (color printer) 150 for color image formation shown in FIG.

2. Photoconductor As the photoconductor 51 shown in FIGS. 1 and 2, there are a single layer type and a multilayer type, and any of them can be applied.
However, it can be used for both positive and negative chargeability, has a simple structure and is easy to manufacture, can suppress film defects when forming a photoreceptor layer, has few interface between layers, and can improve optical characteristics. For these reasons, it is more preferable to apply to a single layer type.
Further, it is preferable to use an amorphous silicon photoreceptor because it is excellent in durability and can easily control the value of the diameter and the surface tension.
Hereinafter, the details of the photoconductor will be described by taking the amorphous silicon photoconductor 51 shown in FIG. 3 as an example.

(1) Conductive Substrate FIG. 3 shows a partial cross-sectional view of the amorphous silicon photoconductor 51. The amorphous silicon photoconductor 51 usually includes a conductive substrate 51a as a core, and a conductive member such as an aluminum alloy. The conductive film may be formed by vapor deposition or the like on the surface of resin or glass.
Here, as a material constituting the conductive substrate, aluminum (Al), SUS (stainless steel), zinc (Zn), copper (Cu), iron (Fe), titanium (Ti), nickel (Ni), chromium Examples thereof include metal materials such as (Cr), tantalum (Ta), tin (Sn), gold (Au), and silver (Ag), and alloy materials thereof.
In addition, the surface of an insulating material such as resin, glass, or ceramic is subjected to conductive treatment with the above-described transparent conductive material such as metal, ITO, or SnO ₂ .
In particular, when an aluminum alloy material is used, it is possible not only to reduce the weight of the photoreceptor at a low cost, but also to have high adhesion to the a-Si photoconductive layer or carrier injection blocking layer, thereby improving the reliability of the photoreceptor. This is preferable in terms of improvement.

(2) Carrier Injection Blocking Layer As shown in FIG. 3, the carrier injection blocking layer 51b uses an amorphous silicon-based material (a-Si-based material) as a base material, and hydrogen (H) or fluorine (F). In addition, it is preferable to further include at least one element selected from Group III, Group IV, and Group V of the periodic table.
It is also preferable to further contain elements such as carbon (C), nitrogen (N), and oxygen (O) as a constituent material of the carrier injection blocking layer.

(3) Photoconductive layer Further, as shown in FIG. 3, as the photoconductive layer 51c made of an amorphous silicon material, when the amorphous state is abbreviated as a-, for example, a-SiC, a-SiCN, It is preferably composed of a-SiNO, a-SiCO, a-SiN, a-Si, a-C, a-CN, a-SiO and the like.
It is also preferable to further contain an element such as hydrogen (H) or fluorine (F) as a part of the amorphous silicon material.

(4) Surface Layer As shown in FIG. 3, the surface layer 51d is composed of amorphous silicon (Si) and / or carbon (C) atoms, and oxygen (O) or nitrogen (N). Among these, it is preferable to contain at least one atom and at least one atom of hydrogen (H) or fluorine (F).
For example, when the ratio of Si atoms to C atoms is expressed as Si _1-x C _x , the Mohs hardness becomes 7 to 11 when x is in the range of 0.4 ≦ x ≦ 1.0. Has been confirmed.
In addition, it is preferable to make the film thickness of this surface layer into the value within the range of 0.1-10 micrometers, and it is further more preferable to set it as the value within the range of 0.3-5 micrometers.

(5) Diameter In addition, it is preferable that the diameter of the photoreceptor is set to a value within a range of 30 to 300 mm.
This is because when the diameter of the photosensitive member is less than 30 mm, a shearing force generated between the photosensitive member and the developing device may be reduced, and a so-called riblet phenomenon may occur.
On the other hand, if the diameter of the photoconductor exceeds 300 mm, the wet image forming apparatus becomes large or the shearing force generated between the photoconductor and the photoconductor becomes excessively large. This is because the image density may decrease.
Accordingly, the diameter of the photoreceptor is more preferably set to a value within the range of 35 to 200 mm, and further preferably set to a value within the range of 40 to 100 mm.

3. Charging Device The charging device 53 shown in FIGS. 1 and 2 can be a known embodiment, but is preferably a scorotron charging device, for example.

4). Developing Device (1) Basic Configuration Further, the liquid developing device 18 shown in FIGS. 1 and 2 includes a liquid developer tank 45 for storing the liquid developer 11 containing toner on the outside thereof.
Further, inside the liquid developing device 18, a developing roller 12, an anilox roller 13, a pumping roller 14, a doctor blade 15, a cleaning blade 33, a charging device 17, a cleaning roller 32, and the like are provided. The developing roller 12, the anilox roller 13, and the scooping roller 14 are each driven to rotate by a driving means including a gear train or the like.
The predetermined liquid developer 11 is supplied by the supply device 18 c in the vicinity of the contact portion between the anilox roller 13 and the pumping roller 14 and on the pumping roller 14.

An anilox roller 13 is provided above the pumping roller 14. A developing roller 12 is further provided above the anilox roller 13.
The pumping roller 14 and the anilox roller 13, and the anilox roller 13 and the developing roller 12 are in contact with each other.

The doctor blade 15 is in contact with the upper part of the anilox roller 13 and on the upstream side of the developing roller 12 in the rotational direction of the anilox roller 13 with respect to the axial direction of the anilox roller 13. The liquid developer 11 supplied to the 13 roller surfaces is held in a groove (concave portion) carved on the surface to regulate the amount of the liquid developer 11.
The photosensitive drum 51 is outside the liquid developing device 18 and is in contact with the developing roller 12.

(2) Liquid developer A liquid developer tank 45 serving as a liquid developer reservoir provided outside the liquid developing device 18 has a liquid developer 11 including toner particles and a carrier that is an insulating liquid. It is stored.
The liquid developer 11 is adjusted so that toner particles are dispersed at a high concentration in a carrier liquid that is a nonpolar, ie, electrically neutral, solvent such as silicone oil.
The toner particles contain a colorant, a resin (binder) and, if necessary, a charge control agent.

The insulating liquid is preferably a paraffin compound, a silicone compound, and a higher fatty acid ester.
This is because toner particles can be uniformly and stably dispersed by using such an insulating liquid.

  Then, the liquid developer 11 is supplied from a developing roller 12 as a developer carrying member to an electrostatic latent image of a portion irradiated with light by the LED exposure device 54 of the photosensitive drum 51, whereby a photosensitive member is obtained. The toner image is developed on the drum 51.

The viscosity of the insulating liquid is preferably set to a value within the range of 15 to 150 mPa · sec (measurement temperature: 25 ° C.).
This is because when the viscosity of the insulating liquid is less than 15 mPa · sec, the toner is liable to settle, and the photoconductor may be insufficiently polished.
On the other hand, when the viscosity of the insulating liquid exceeds 150 mPa · sec, the toner tends to disperse unevenly, and the photoconductor may still be insufficiently polished.
Note that it is preferable to use an insulating liquid constituting a part of the liquid developer and an insulating liquid having the same components and viscosity as the insulating liquid constituting a part of the liquid abrasive described later.

(3) Developer Roller Further, the development roller 12 receives the supply of the liquid developer 11 from the anilox roller 13, forms a thin layer of the liquid developer on the surface thereof, and applies the liquid developer to the photosensitive drum 51. Then, the electrostatic latent image formed on the photosensitive drum 51 is developed.
The surface of the developing roller 12 is a resin-coated conductive rubber layer, which enhances toner releasability. And it is desirable to use a rubber roller having a hardness of 35 to 50 degrees (JIS A).
Further, the toner in the thin layer of the liquid developer 11 formed on the surface of the developing roller 12 is configured to be applied with an electric field by a charging device 17 described later. That is, the toner that has been subjected to the predetermined charging process is pushed to the surface side of the developing roller 12 by an electrical repulsion effect generated in the charging device 17.

(4) Charging Device Although the charging device 17 shown in FIG. 1 is an example, it is a corotron charging device and is upstream of the photosensitive drum 51 in the rotation direction of the developing roller 12. It is provided opposite to the developing roller 12, and the control of the output potential and the operation timing is performed by a control means (not shown).
The charging device 17 is provided to face the developing roller 12, and a voltage having the same polarity as the charging polarity of the toner component of the liquid developer 11 is applied to the corona wire of the charging device 17.
Therefore, when the charging device 17 is turned on, in the thin layer of the liquid developer 11 on the surface of the developing roller 12 facing the charging device 17, the toner component in the liquid developer 11 is caused to be charged by the electric field action. It is configured to be repelled by the electric field generated by 17 and to be assembled on the developing roller 12 side in the thin layer of the liquid developer 11 (toner compaction process).

(5) Developing roller cleaning means Further, as shown in FIG. 1, a cleaning roller 32 for cleaning the developing roller 12 is provided as a developing roller cleaning means. A cleaning blade 33 as a mechanical removing unit is provided on the downstream side in the rotation direction so as to contact the developing roller 12.
Although this cleaning blade 33 is an example, it is a plate member made of urethane rubber having a thickness of 1.8 mm and a rubber hardness of 77 degrees, and one end of the blade in the longitudinal direction with respect to the developing roller 12 in the axial direction thereof, The counter abuts accurately with a deflection of 1 mm and a pressure contact angle of 10 degrees.
As shown in FIG. 1, the liquid developer 11 on the developing roller 12 that has not been collected by the cleaning roller 32 is mechanically removed by the cleaning blade 33. In other words, the liquid developer 11 that has been mechanically removed is recycled or collected and then discarded to the outside.

5. Photoconductor Polishing Device (1) Basic Configuration Examples of the photoconductor 51 polishing device 58 shown in FIGS. 1 and 2 include a polishing roller, a polishing brush, and a polishing cloth.
In particular, a polishing roller with a rotating polishing device is a preferred embodiment because it is easy to supply a liquid abrasive and can control the polishing force to achieve appropriate polishing without damaging the surface of the photoreceptor.

Further, as shown in FIG. 1, a cleaning blade 57 is used in combination with a polishing apparatus 58.
This is because the surface of the photoconductor is polished by a polishing roller using a polishing roller, and the polishing agent used for polishing and the substance released from the photoconductor by polishing are basically removed by the cleaning blade 57. is there.
At that time, by supplying a liquid abrasive to at least the polishing apparatus 58, the surface of the photoreceptor can be properly polished without being damaged.

In addition, as shown in FIGS. 4A to 4B, in order to effectively remove the developer such as toner remaining on the photoreceptor after the transfer, in addition to the cleaning blade 57 shown in FIG. It is also preferable to provide the second cleaning blade 60 at an upstream position in the rotation direction of the photosensitive member.
That is, after the surface of the photoconductor 51 is polished using the polishing roller 58a included in the polishing device 58, the developing process is not performed immediately, but the photoconductor 51 is used using the second cleaning blade 60. It is preferable to further clean the surface.

4A to 4B, the polishing apparatus 58 includes a polishing roller 58a, and an abrasive supply unit 58b for supplying a liquid abrasive 59 to the polishing roller 58a is provided. Further, it is preferable to provide them.
The reason for this is that the liquid abrasive can be reliably supplied to the polishing roller by configuring in this way, and the polishing roller can further appropriately and appropriately apply the surface of the photoreceptor via the predetermined liquid abrasive. This is because it can be effectively polished.

Further, as shown in FIGS. 4A to 4B, a storage part 58c for holding the liquid abrasive 59 is provided, and the liquid abrasive 59 held in the storage part 58c is supplied to the abrasive supply means. It is preferable that 58b is lifted and supplied to the polishing roller 58a.
The reason for this is that the liquid abrasive held in the storage unit can be reliably supplied to the polishing roller by the abrasive supply means, and the polishing roller is a predetermined liquid abrasive. This is because the surface of the photoconductor can be polished more moderately and effectively through the above.

4A to 4B, it is preferable that a driving device (rotating support member) 58d for bringing the polishing device 58 into and out of contact with the photosensitive member 51 is further provided.
In other words, it is preferable that the polishing device 58 be configured to be separated from the photoreceptor 51 during non-cleaning.
The reason for this is that the configuration of the drive-type polishing apparatus makes it possible to separate the polishing apparatus from the photosensitive member during non-cleaning, so that liquid polishing is performed inside the developing device. This is because the agent can be effectively prevented from being mixed.
Note that, as an example, the rotation support member 58d is provided at the end of the polishing device 58 as a driving device so that the position of the polishing device 58 can be changed and can be separated from the photoconductor 51 accurately and quickly. It is preferable to provide it.

(2) Liquid abrasive In addition, a liquid abrasive containing inorganic particles is used.
That is, with this configuration, the surface of the photoreceptor can be appropriately polished by a polishing apparatus via a predetermined liquid abrasive. Therefore, the occurrence of filming can be prevented over a long period of time, and thereby excellent image characteristics can be stably obtained.

In addition, since the electrical insulating property is high and the hardness is appropriate, the inorganic particles are at least one selected from the group consisting of titanium oxide and aluminum oxide .
This is because the polishing apparatus can polish the surface of the photoreceptor more appropriately and effectively through the liquid abrasive containing the predetermined inorganic particles .

Further, the content of the inorganic particles is preferably set to a value in the range of 2 to 30% by weight when the total amount of the liquid abrasive is 100% by weight.
This is because the polishing apparatus can polish the surface of the photoconductor moderately and effectively through a liquid abrasive containing a predetermined amount of inorganic particles. .
More specifically, when the content of the inorganic particles is less than 2% by weight, the existence probability of the inorganic particles is reduced or unevenly dispersed, and the photoconductor is not sufficiently polished. This is because there may be cases.
On the other hand, if the content of the inorganic particles exceeds 30% by weight, the inorganic particles are likely to settle, and the photoconductor may still be insufficiently polished.
Therefore, the content of the inorganic particles is more preferably 3 to 28% by weight when the total amount of the liquid abrasive is 100% by weight, more preferably 4 to 25% by weight. More preferably, it is a value.

Further, the average particle diameter of the inorganic particles is set to a value within the range of 0.5 to 10 μm .
The reason for this is that, by configuring in this way, the polishing apparatus can further appropriately and effectively polish the surface of the photoreceptor via a liquid abrasive containing inorganic particles having a predetermined average particle diameter. Because.
More specifically, if the average particle diameter of the inorganic particles is less than 0.5 μm , the photoconductor may be insufficiently polished.
On the other hand, if the average particle size of the inorganic particles exceeds 10 μm, the inorganic particles are likely to settle, and the photoconductor may still be insufficiently polished .

Moreover, it is preferable that a liquid abrasive | polishing agent contains at least one selected from the group which consists of a paraffin compound, a silicone compound, and a higher fatty acid ester as a solvent.
The reason for this is that, by configuring in this way, the polishing apparatus polishes the surface of the photoreceptor more appropriately and effectively via a liquid abrasive containing inorganic particles in a predetermined solvent. This is because it can be done.

Further, the viscosity of the liquid abrasive is not particularly limited, but is preferably set to a value within the range of 10 to 150 mPa · sec (measurement temperature: 25 ° C.).
The reason for this is that by limiting the viscosity of the liquid abrasive as described above, the polishing apparatus can further appropriately and effectively polish the surface of the photoreceptor via the liquid abrasive having a predetermined viscosity. Because.
More specifically, when the viscosity of the liquid abrasive becomes a value of less than 10 mPa · sec, the inorganic particles are likely to settle, and the polishing of the photoconductor may still be insufficient.
On the other hand, when the viscosity of the liquid abrasive exceeds 150 mPa · sec, the existence probability of the inorganic particles is reduced or unevenly dispersed, and the photoconductor is not sufficiently polished. This is because there are cases.
Therefore, the viscosity of the liquid abrasive is more preferably set to a value within the range of 20 to 120 mPa · sec, and further preferably set to a value within the range of 30 to 130 mPa · sec.

6). Cleaning Operation A cleaning operation using a liquid abrasive will be described with reference to FIGS.
FIG. 4A shows a state in which the developing roller 18 as the liquid developing device operates to develop the liquid developer, that is, a state in which the developing process is performed, and is included in the polishing device 58. The polishing roller 58a is in a state of being separated from the photoreceptor 51.
Therefore, the liquid abrasive held by the polishing roller 58a of the polishing apparatus adheres to the surface of the photoreceptor, and as a result, the liquid abrasive is mixed into the developing device, resulting in a change in the characteristics of the liquid developer, There is no risk of disturbing the development process.

However, in the case where the developing process is performed immediately after the cleaning process is performed using the polishing roller 58a, after the predetermined time has elapsed, the photosensitive member 51 is further cleaned by the second cleaning blade 60. It is preferable that the development state shown in FIG.
This is because the inorganic particles contained in the liquid abrasive may adhere to the photoconductor 51 immediately after the cleaning process is performed using the polishing roller 58a.

On the other hand, FIG. 4B shows a standby state in which the driving type developing roller 18 as the liquid developing device stops operating and the liquid developer is not developed. A state is shown in which a predetermined polishing process is performed by contacting the photosensitive member 51.
That is, after the development process shown in FIG. 4A is performed or after the development process is periodically stopped, the drive-type development roller 18 is rotated by a predetermined angle (θ2) by the rotation support member 18d. The photoconductor 51 is separated by a distance (L2).

In synchronization therewith, the polishing device 58 that has been separated from the photoconductor 51 by the distance (L1) is rotated by a predetermined angle (θ1) by the rotation support member 58c and is brought into contact with the photoconductor 51.
Therefore, the polishing device 58 can come into contact with the photoconductor 51 while the liquid developing device 18 is separated from the photoconductor 51 to perform a predetermined polishing process.
Therefore, as shown in FIG. 4B, there is no fear that the liquid abrasive is collected by the liquid developing device 18 and the polishing effect cannot be obtained, and the liquid abrasive is mixed into the liquid developing device 18 as described above. Therefore, the polishing device 58 can independently carry out a predetermined cleaning on the surface of the photoreceptor 51.

[Second Embodiment]
The second embodiment is
A photoreceptor,
A charging device for charging the photoconductor to a predetermined potential;
A developing device for supplying a liquid developer in which toner is dispersed in an insulating liquid to a photoreceptor;
A cleaning blade for cleaning the toner remaining on the surface of the photoreceptor;
A polishing apparatus for polishing the surface of the photoreceptor;
A wet image forming method using
In the polishing apparatus, a liquid abrasive containing inorganic particles is used, and the inorganic particles are at least one selected from the group consisting of titanium oxide, aluminum oxide, and zirconium oxide, and the average particle size of the inorganic particles is 0. A value in the range of 5-10 μm , and
A wet-type image forming apparatus, further comprising a driving device for bringing the developing device into and out of contact with the photosensitive member, wherein the developing device is separated from the photosensitive member by the driving device during cleaning by the polishing device. Is the method.
Hereinafter, the wet image forming method using the predetermined wet image forming apparatus according to the second embodiment will be specifically described within a range not overlapping with the first embodiment.

1. Development Step The development step is a step of supplying a liquid developer in which toner is dispersed in an insulating liquid to a photosensitive member having a latent image by a developing device to make the latent image visible.
Therefore, in the second embodiment, a known development process can be performed as it is.
As described above, when the developing process shown in FIG. 4A is performed, the developing roller 18 as a liquid developing device contacts the photoconductor 51, while the polishing device 58 contacts the photoconductor 51. On the other hand, they are separated by a predetermined distance (L1).
Therefore, by adopting the configuration of the drive type polishing device 58 in this way, a predetermined developing roller can be driven independently, and the liquid abrasive used in the polishing device 58 is mixed in the developer. Can be effectively prevented.

2. Cleaning Step If a liquid abrasive containing inorganic particles is used, a known polishing apparatus, for example, a polishing roller can be used as it is.
As described above, when the cleaning process shown in FIG. 4B is performed, the developing roller 18 as a liquid developing device is driven, so that its position is movable with respect to the photoreceptor 51. , They are separated by a predetermined distance (L2).
Therefore, by adopting such a drive-type developing roller configuration, at the time of cleaning, only a predetermined polishing apparatus can be driven independently, and the liquid abrasive used in the polishing apparatus 58 is developed in the developing apparatus. It can prevent effectively that it mixes in an agent.
The cleaning process is preferably performed after the desired development process is performed. Alternatively, for example, the development process may be periodically stopped every time 1000 sheets of A4 paper are developed. preferable.

According to the wet image forming apparatus and the wet image forming method of the present invention, it is possible to effectively clean the photosensitive member without damaging it by providing a polishing apparatus and using a predetermined liquid abrasive. Therefore, it is possible to prevent filming from occurring on the photoreceptor for a long period of time.
Therefore, the wet image forming apparatus of the present invention can be suitably applied as various printers, facsimiles, copiers and the like.

It is a figure provided in order to demonstrate the wet image forming apparatus which concerns on this invention. 1 is a diagram provided for explaining a tandem wet color image forming apparatus according to the present invention. FIG. It is a fragmentary sectional view provided in order to demonstrate an amorphous silicon photoconductor. (A)-(b) is a figure provided in order to demonstrate the cleaning operation | movement in the wet image forming apparatus which concerns on this invention. It is a figure provided in order to demonstrate the conventional cleaning means (the 1). It is a figure provided in order to demonstrate the conventional cleaning means (the 2). It is a figure provided in order to demonstrate the conventional cleaning means (the 3).

Explanation of symbols

2: image forming unit 3: paper storage unit 4: secondary transfer unit 5: fixing unit 6: discharge unit 7: paper transport unit 10: wet image forming apparatus 11: liquid developer 12: developer carrier 13: anilox roller 14: Pumping roller 15: Doctor blade 17: Charging device 18: Liquid developing device (developing roller)
18a: Collected liquid reservoir 18b: Waste liquid reservoir 18c: Supply device 20: Primary transfer roller 21: Intermediate transfer belt 22: Cleaning unit 32: Cleaning roller 33: Cleaning blade 45: Liquid developer tank 51: Photoconductor drum 52: Static elimination Device 53: Charging device 54: LED exposure device 57: Cleaning blade (first cleaning blade)
58: Polishing device 58a: Polishing roller 58b: Abrasive supply means 58c: Storage unit 59: Liquid abrasive 60: Second cleaning blade 61: Paper 150: Color printer (wet image forming apparatus)

Claims (9)

A photoreceptor,
A charging device for charging the photoconductor to a predetermined potential;
A developing device for supplying a liquid developer in which a toner is dispersed in an insulating liquid to the photoreceptor;
A cleaning blade for cleaning toner remaining on the surface of the photoreceptor;
A polishing apparatus for polishing the surface of the photoreceptor;
A wet image forming apparatus comprising:
In the polishing apparatus, using a liquid abrasive containing inorganic particles,
The inorganic particles are at least one selected from the group consisting of titanium oxide, aluminum oxide, and zirconium oxide,
The average particle size of the inorganic particles is a value within the range of 0.5 to 10 μm,
And,
A driving device for bringing the developing device into and out of contact with the photosensitive member is further provided, and the developing device is separated from the photosensitive member by the driving device during cleaning by the polishing device. A wet image forming apparatus.   2. The wet image formation according to claim 1, wherein the polishing apparatus includes a polishing roller, and further provided with an abrasive supply means for supplying the liquid abrasive to the polishing roller. apparatus.   The wet content according to claim 1 or 2, wherein the content of the inorganic particles is set to a value in the range of 2 to 30% by weight when the total amount of the liquid abrasive is 100% by weight. Image forming apparatus.   The wet type according to any one of claims 1 to 3, wherein the liquid abrasive contains at least one selected from the group consisting of paraffin compounds, silicone compounds, and higher fatty acid esters as a solvent. Image forming apparatus.   The wet image forming apparatus according to claim 1, wherein the viscosity of the liquid abrasive is set to a value within a range of 10 to 150 mPa · sec (measurement temperature: 25 ° C.). The wet image forming apparatus according to any one of claims 1 to 4, further comprising a driving device for bringing the polishing device into and out of contact with the photosensitive member . A photoreceptor,
A charging device for charging the photoconductor to a predetermined potential;
A developing device for supplying a liquid developer in which a toner is dispersed in an insulating liquid to the photoreceptor;
A cleaning blade for cleaning toner remaining on the surface of the photoreceptor;
A polishing apparatus for polishing the surface of the photoreceptor;
A wet image forming method using
In the polishing apparatus, using a liquid abrasive containing inorganic particles,
The inorganic particles are at least one selected from the group consisting of titanium oxide, aluminum oxide, and zirconium oxide,
The average particle size of the inorganic particles is a value within the range of 0.5 to 10 μm,
And,
A driving device for bringing the developing device into and out of contact with the photosensitive member is further provided, and the developing device is separated from the photosensitive member by the driving device during cleaning by the polishing device. A wet image forming method. The polishing apparatus includes a polishing roller and an abrasive supply means,
8. The wet image forming method according to claim 7 , wherein when the surface of the photoconductor is cleaned, the abrasive supply unit supplies the liquid abrasive to the polishing roller. The polishing apparatus, the Yes photosensitive body driving device for contacting and separating further relative provided, wherein the time of non-cleaning by grinding apparatus, claims the developing device, characterized in that to separate from the photoreceptor 9. The wet image forming method according to 7 or 8 .

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