JP2009229687A - Wet type image forming apparatus and wet type image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wet type image forming apparatus including a predetermined polishing device, reduced in filming to an amorphous silicon photoreceptor, and also to provide a wet type image forming method. <P>SOLUTION: This wet type image forming apparatus includes the amorphous silicon photoreceptor, a charging device, and a liquid developing device. This wet type image forming method uses the above wet type image forming apparatus. The apparatus further includes the polishing device for polishing the surface of the amorphous silicon photoreceptor, wherein the surface of the polishing device contains polishing particles having a Mohs hardness ranging from 3 to 6. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wet image forming apparatus including an amorphous silicon photoconductor and a wet image forming method using the same, and more particularly to a wet image forming apparatus including a predetermined polishing apparatus and an amorphous silicon photoconductor with little filming. And a wet image forming method using the same.

In a wet image forming apparatus provided with an amorphous silicon photoconductor, a liquid developing device is mounted as a developing device, and an electrostatic latent image formed on the amorphous silicon photoconductor is supplied from the liquid developing device. Develop with liquid developer.
At this time, when the development is continuously performed, filming of the toner with respect to the amorphous silicon 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 amorphous silicon photosensitive member, and as a result, the image characteristics are remarkably deteriorated.

However, in a wet image forming apparatus provided with an amorphous silicon photoreceptor, there is no suitable polishing apparatus yet.
That is, in the wet image forming apparatus, although the surface of the amorphous silicon photoconductor is peculiarly covered with the non-water-soluble solvent contained in the developer, the surface of the amorphous silicon photoconductor is excessive. In the case of polishing, it was found that the surface of the amorphous silicon photosensitive member was easily damaged as well as the coating of the water-insoluble solvent was easily peeled off.

On the other hand, the dry type image forming apparatus, unlike the wet type image forming apparatus, has been proposed the following polishing apparatus because there is no particularity that it is always covered with a water-insoluble solvent contained in the developer. ing.
First, in an electrophotographic apparatus provided with a cleaning blade for removing residual toner on the surface of the photoreceptor, a cleaning roller provided with a conductive polyurethane coating film containing abrasive particles is used as a cleaning means for assisting the cleaning blade. Providing further is proposed (for example, refer to Patent Document 1).
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 2).
More specifically, as shown in FIG. 5, 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 (for example, See Patent Document 2).

In addition, a polishing tape that suppresses uneven polishing has been proposed when polishing the surface of an amorphous silicon photoreceptor using a polishing apparatus in which a polishing tape is wound around a polishing roller (see, for example, Patent Document 3).
More specifically, as shown in FIG. 6, the arithmetic average roughness measured in the field of view of 10 μm × 10 μm by an atomic force microscope is (Ra), and is continuously wound around at least two polishing rollers 530. In the method in which the polishing tape 531 is fed while being pressed and abutted, and the outermost surface of the photosensitive member 500 is polished to an arithmetic average roughness (Ra) of 25 nm or less, the photosensitive member 500 is held and rotated by a holding mechanism 520. A continuous polishing tape 531 is fed while being brought into pressure contact with the surface of the amorphous silicon photosensitive member 500 by at least two polishing rollers 530, and SiC, Al ₂ O for polishing the outermost surface of the amorphous silicon photosensitive member 500 ₃ , a polishing tape 531 containing Fe ₂ O ₃ or the like has been proposed.
Japanese Patent No. 2631935 (Claims) JP 2004-126217 A (Claims) JP-A-8-76639 (Claims)

However, in the polishing means and the polishing tape disclosed in Patent Documents 1 to 3, the amorphous silicon photoconductor is excessively polished when used in a wet image forming apparatus provided with an amorphous silicon photoconductor. There was a problem that the characteristics were likely to deteriorate.
That is, in the wet image forming apparatus, as described above, when the surface of the amorphous silicon photoconductor is excessively polished, the coating of the non-aqueous solvent is likely to occur, and the surface of the amorphous silicon photoconductor There was a problem that high quality image characteristics could not be obtained for a long time.

Thus, as a result of intensive studies, the present inventors have found that the occurrence of filming can be prevented over a long period of time by containing abrasive particles having a Mohs hardness in a predetermined range on the surface of the polishing apparatus.
That is, according to the present invention, the surface of the amorphous silicon photoconductor is appropriately polished by a predetermined polishing apparatus to prevent filming over a long period of time, and to achieve excellent image characteristics stably. An object of the present invention is to provide an image forming apparatus and a wet image forming method using the same.

According to the present invention,
An amorphous silicon photoreceptor,
A charging device for charging the amorphous silicon photosensitive member to a predetermined potential;
A liquid image development apparatus that supplies a liquid developer in which toner is dispersed in an insulating liquid to an amorphous silicon photoreceptor, and a wet image forming apparatus comprising:
Further equipped with a polishing apparatus for polishing the surface of the amorphous silicon photoreceptor,
There is provided a wet image forming apparatus characterized in that the surface of the polishing apparatus contains abrasive particles having a Mohs hardness in the range of 3 to 6, and the above-described problems can be solved.
In other words, according to the present invention, by appropriately polishing the surface of the amorphous silicon photoreceptor, it is possible to prevent filming over a long period of time and stably obtain excellent image characteristics.
It has been found that the Mohs hardness on the surface of the amorphous silicon photoreceptor is usually a value in the range of 8-11.

Further, in constituting the wet image forming apparatus of the present invention, it is preferable that the abrasive particles are exposed and present on the surface of the polishing apparatus.
With this configuration, the surface of the amorphous silicon photoreceptor can be effectively polished with a relatively small amount of abrasive particles.

In configuring the wet image forming apparatus of the present invention, it is preferable to provide a polishing layer containing abrasive particles on the surface of the polishing apparatus.
With this configuration, it is possible to easily replace only the polishing layer even if the polishing layer containing the abrasive particles is deteriorated by use as well as the initial polishing layer.
Moreover, by comprising in this way, manufacture of a grinding | polishing apparatus becomes easy and it becomes economically advantageous.

Further, in configuring the wet image forming apparatus of the present invention, the polishing apparatus is preferably an elastic roller including a resin foam as a base material.
With this configuration, the pressing force against the amorphous silicon photoconductor can be made uniform, and the surface of the amorphous silicon photoconductor can be polished more appropriately.

In configuring the wet image forming apparatus of the present invention, the abrasive particles are preferably at least one selected from the group consisting of melamine resin powder, fluororesin powder, and glass beads.
With this configuration, the surface of the amorphous silicon photoreceptor can be effectively polished with a relatively small amount of abrasive particles.
Such abrasive particles are not only easy to adjust the average particle diameter and specific gravity, but also inexpensive and economical.

In configuring the wet image forming apparatus of the present invention, it is preferable that the outer shape of the abrasive particles is a polyhedral shape.
With this configuration, the surface of the amorphous silicon photoreceptor can be effectively polished with a relatively small amount of abrasive particles.

In configuring the wet image forming apparatus of the present invention, the average particle size of the abrasive particles is preferably set to a value within the range of 0.001 to 100 μm.
With this configuration, the surface of the amorphous silicon photoreceptor can be effectively polished with a relatively small amount of abrasive particles.

In configuring the wet image forming apparatus of the present invention, the content of the abrasive particles is preferably set to a value in the range of 1 to 50% by weight with respect to the total amount of the polishing apparatus.
With this configuration, the surface of the amorphous silicon photoconductor can be polished more appropriately and effectively, and filming can be effectively prevented.

Another aspect of the present invention is as follows:
An amorphous silicon photoreceptor,
A charging device for charging the amorphous silicon photosensitive member to a predetermined potential;
A liquid developing device for supplying a liquid developer in which toner is dispersed in an insulating liquid to the amorphous silicon photosensitive member;
A wet image forming method using a polishing apparatus for polishing the surface of an amorphous silicon photoreceptor,
A wet image forming method comprising a step of polishing the surface of an amorphous silicon photoreceptor using a polishing apparatus containing polishing particles having a Mohs hardness in the range of 3 to 6 on the surface.
That is, according to the wet image forming method of the present invention, the surface of the amorphous silicon photoconductor is appropriately polished using a predetermined polishing apparatus, thereby preventing filming over a long period of time and excellent image characteristics. Can be obtained stably.

[First Embodiment]
The first embodiment of the present invention, as illustrated in FIG.
An amorphous silicon photoreceptor 51;
A charging device 53 for charging the amorphous silicon photoconductor 51 to a predetermined potential;
A wet image forming apparatus 10 comprising: a liquid developing device 18 that supplies a liquid developer 11 in which toner is dispersed in an insulating liquid to an amorphous silicon photoreceptor 51;
A polishing device 58 for polishing the surface of the amorphous silicon photoconductor 51 is further provided.
And as illustrated in FIGS. 2A to 2C, the surface of the polishing apparatus 58 contains abrasive particles 58a having a Mohs hardness in the range of 3 to 6.
Hereinafter, as shown in FIG. 3, taking as an example the case of a tandem type wet image forming apparatus (color printer) 150 for color image formation, the wet image forming apparatus 10 illustrated in FIG. 1 and the polishing apparatus 58 illustrated in FIG. Will be described in detail.

1. Basic Configuration A color printer 150 shown in FIG. 3 is arranged in an upper main body 150A in which various units and parts for image formation are stored, and a lower part of the upper main body 150A, and a liquid developer circulating device for each color. LY, LM, LC, and LB (mixed liquid supply system) are comprised from the lower side main-body part 150B.
In the upper main body 150A, a tandem-type image forming unit 2 that forms a toner image based on image data, a paper storage unit 3 that stores paper, and a toner image formed by the image forming unit 2 are printed on paper. From the secondary transfer unit 4 to be transferred upward, the fixing unit 5 for fixing the transferred toner image on the paper, the discharge unit 6 for discharging the fixed paper, and from the paper storage unit 3 to the discharge unit 6 And a paper transport unit 7 for transporting paper.

Here, the image forming unit 2 corresponds to the intermediate transfer belt 21, the cleaning unit 22 of the intermediate transfer belt 21, and each color of yellow (Y), magenta (M), cyan (C), and black (Bk). Image forming units FY, FM, FC, and FB.
Further, the intermediate transfer belt 21 is wider than the maximum length sheet in the direction perpendicular to the usable sheet transport direction and has an endless shape, that is, a loop-shaped member. It is circulated and driven.
Hereinafter, in a state where the intermediate transfer belt 21 is driven, a surface facing outward is referred to as a front surface, and an opposite surface is referred to as a back surface.

Further, four image forming units FY, FM, FC, and FB are arranged in the vicinity of the intermediate transfer belt 21 and arranged between the cleaning unit 22 of the intermediate transfer belt 21 and the secondary transfer unit 4.
Note that the order of arrangement of the image forming units FY, FM, FC, and FB is not limited to this, but this arrangement is preferable in consideration of the influence of the color mixture on the completed image.

The image forming units FY, FM, FC, and FB include a photosensitive drum 51, a charging device 53, an LED exposure device 54, a developing device 18, a primary transfer roller 20, a polishing device 58, and a static elimination device. 52.
In correspondence with the image forming units FY, FM, FC, and FB, liquid developer circulating devices LY, LM, LC, and LB are provided, respectively, so that the liquid developer of each color is supplied and recovered. It has become.

2. Amorphous Silicon Photoreceptor (1) Conductive Substrate FIG. 4 shows a partial cross-sectional view of the amorphous silicon photoreceptor 51. The amorphous silicon photoreceptor 51 usually includes a conductive substrate 51a as a core, and is an aluminum alloy. It is also possible to use a conductive member such as a conductive member, or to deposit a conductive film 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 Further, as shown in FIG. 4, the carrier injection blocking layer 51b uses an amorphous silicon-based material (a-Si-based material) as a base material, and H (hydrogen atoms) or F ( A fluorine atom) and 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 C, N, and O as a constituent material of the carrier injection blocking layer.

(3) Photoconductive layer Further, as shown in FIG. 4, as the photoconductive layer 51c made of an amorphous silicon-based 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 H or F as a part of the amorphous silicon material.

(4) Surface Layer As shown in FIG. 4, 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 , if x is in the range of 0.4 ≦ x ≦ 1.0, the Mohs hardness is in the range of 8-11. It has been confirmed that
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.

4). Charging Device The charging device may be a known embodiment, but for example, a scorotron charging device is preferable.

5. Liquid Developing Device Further, as shown in FIG. 1, the liquid developing device 18 includes a liquid developer tank 45 for storing the liquid developer 11 containing toner, 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 unit 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.

A liquid developer storage tank (liquid developer tank) 45 provided outside the liquid developing device 18 stores the liquid developer 11 including toner particles and a carrier that is an insulating liquid.
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 are composed of a resin (binder) such as epoxy, a charge control agent that gives a predetermined charge to the toner, a color pigment, and the like.
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. A toner image can be developed on the drum 51.

6). Polishing Device (1) Mohs Hardness of Abrasive Particles As shown in FIG. 2 (a), abrasive particles 58a having a Mohs hardness in the range of 3 to 6 on the surface of the polishing device 58 (including the case where it exists inside). It is characterized by containing.
The reason for this is that if the Mohs hardness of the abrasive particles present on the surface of the polishing apparatus is less than 3, the surface polishing of the amorphous silicon photoreceptor becomes insufficient and it is difficult to prevent filming over a long period of time. Because.
On the other hand, if the Mohs hardness of the abrasive particles exceeds 6, the surface polishing of the amorphous silicon photoreceptor becomes excessive, and on the contrary, the image characteristics may deteriorate.
Accordingly, the polishing apparatus preferably contains abrasive particles having a Mohs hardness in the range of 3 to 5, and more preferably contains abrasive particles having a Mohs hardness in the range of 3 to 4.
The Mohs hardness of the abrasive particles can be measured using a Mohs hardness meter.

(2) Types of abrasive particles The type of abrasive particles is not particularly limited as long as the value of the Mohs hardness is within a predetermined range. For example, melamine resin powder (Mohs hardness: 3 to 4) And at least one selected from the group consisting of fluororesin powder (Mohs hardness: 3-4) and glass beads (Mohs hardness: 6-7).
This is because the surface of the amorphous silicon photosensitive member can be effectively polished with a relatively small amount of abrasive particles by constituting such abrasive particles.
In addition, such abrasive particles are not only easy to adjust the average particle diameter and specific gravity, but also inexpensive and economical.
In addition, if it is a melamine resin powder, it is easy to make an external shape into a polygon, and since specific gravity is 2 g / cm < ³ > or less normally and dispersibility is more preferable, it is a more preferable abrasive particle. It is.
Glass beads are more preferable abrasive particles because they are not only excellent in durability but also have a specific gravity of usually 3 g / cm ³ or less and good dispersibility.

(3) Arrangement of Abrasive Particles As shown in FIGS. 2A to 2C, abrasive particles 58, 58 ″, 58 ″ ″ (including the abrasive layer 58 ′) are provided on the surface of the abrasive particles. 58a is preferably exposed and present.
This is because the surface of the amorphous silicon photosensitive member can be effectively polished with a relatively small amount of abrasive particles.
2A and 2B are examples in which some abrasive particles 58a are partially exposed on the surfaces of the polishing apparatuses 58 and 58 '. FIG. In this example, the abrasive particles 58a are exposed on the surface of the polishing device 58 ″.

(4) External shape of abrasive particles The external shape of the abrasive particles is preferably a polyhedral shape.
This is because the surface of the amorphous silicon photosensitive member can be effectively polished with a relatively small amount of abrasive particles.
Moreover, as a polyhedron shape, what is necessary is just the solid shape which has a some angle | corner, Usually, it is preferable that it is a 6-30 plane, and it is more preferable that it is an 8-20 plane.
The outer shape of the abrasive particles can be confirmed using an electron microscope or a particle size distribution meter.

(5) Average Particle Size of Abrasive Particles The average particle size of the abrasive particles is not particularly limited, but is usually preferably a value within the range of 0.001 to 100 μm.
This is because if the average particle size of the abrasive particles is less than 0.001 μm, the polishing effect on the surface of the amorphous silicon photoreceptor may be significantly reduced.
On the other hand, if the average particle size of the abrasive particles exceeds 100 μm, the polishing effect on the surface of the amorphous silicon photoreceptor may be excessively exhibited.
Accordingly, the average particle size of the abrasive particles is more preferably set to a value within the range of 0.01 to 30 μm, and further preferably set to a value within the range of 0.1 to 10 μm.
The average particle size of the abrasive particles can be measured using an electron microscope or a particle size distribution meter.

(6) Content of abrasive particles The content of abrasive particles is not particularly limited, but is usually 1 to 50 with respect to the total amount of the polishing apparatus (total amount of abrasive particles and substrate). A value within the range of% by weight is preferred.
This is because if the content of the abrasive particles is less than 1% by weight, the polishing effect on the surface of the amorphous silicon photoreceptor may be significantly reduced.
On the other hand, if the content of the abrasive particles exceeds 50% by weight, the polishing effect on the surface of the amorphous silicon photoreceptor may be excessively exhibited or it may be difficult to uniformly disperse.
Therefore, the content of the abrasive particles is more preferably set to a value within the range of 3 to 30% by weight, and further to a value within the range of 5 to 20% by weight, based on the total amount of the polishing apparatus. preferable.

(7) Base Material (7) -1 Main Base Material As shown in FIGS. 2A to 2C, the polishing apparatus 58, 58 ″, 58 ″ ′ includes a group containing abrasive particles 58a. The material 58b is not particularly limited, but is preferably a resin foam, for example.
The reason for this is that by including abrasive particles in such a resin foam, the pressing force against the amorphous silicon photoconductor can be made uniform, and the surface of the amorphous silicon photoconductor can be polished more appropriately. This is because it can.

The type of the resin foam is not particularly limited. For example, urethane resin foam, styrene resin foam, olefin resin foam, silicone resin foam, melamine resin foam, phenol resin foam, etc. Is mentioned.
In particular, a urethane resin foam is a preferred resin foam because it can be prepared from a polyol compound and an isocyanate compound without using a foaming agent and is excellent in durability.

(7) -2 Sub-Substrate Moreover, as shown in FIG. 2C, it is preferable to contain a fibrous substance 58d as a sub-substrate constituting a part of the polishing apparatus 58 ''.
The reason is that the durability of the polishing apparatus is remarkably improved by containing the fibrous substance. Further, the retention of abrasive particles in the polishing apparatus is also remarkably improved.
That is, since the fibrous substance becomes a part of the matrix and the abrasive particles enter and adhere between them, not only the durability of the polishing apparatus is improved but also the falling off of the abrasive particles is reduced.

Here, as a kind of fibrous substance, it is preferable that it is the fiber comprised from the polyamide resin, the olefin resin, the polyester resin, the polyurethane resin, and glass.
And it is usually preferable to make the diameter of a fibrous substance into the range of 0.1-100 micrometers, and to make the length into the value within the range of 0.1-5 mm.
In addition, when adding a fibrous substance, it is set as the value within the range of 0.1-30 weight% with respect to the whole quantity of polishing apparatus (Abrasive particle | grains, a base material, and the total amount of a fibrous substance). Preferably, the value is in the range of 0.5 to 20% by weight, more preferably in the range of 1 to 10% by weight.

(8) Polishing Layer As shown in FIG. 2A, the surface of the core material 58c included in the polishing apparatus 58 may be provided with a polishing layer 58 ′ composed of a main base material 58b containing abrasive particles 58a. preferable.
The reason for this is that the polishing layer can be easily replaced even when it is deteriorated by use as well as when the polishing layer containing the abrasive particles is initially defective. Because.
Further, this configuration facilitates the manufacture of the polishing apparatus, which is economically advantageous.

Here, the polishing layer is more effective by being provided on the surface portion of the polishing apparatus (polishing roller).
That is, the polishing layer on the surface of the polishing apparatus can be easily replaced.
In addition, by providing the surface of the polishing apparatus in this way, it becomes easier to manufacture the polishing apparatus, which is economically advantageous.

7). Cleaning Blade Further, as shown in FIG. 1, a cleaning blade 57 is used together with a polishing device 58.
The reason for this is that toner remaining on the photoreceptor is basically removed by a cleaning blade, and relatively small removals such as toner constituent resin and deposits remaining on the photoreceptor are removed by a polishing roll. This is because it can be removed.

[Second Embodiment]
The second embodiment of the present invention is a wet image forming method using the wet image forming apparatus 10 illustrated in FIG.
An amorphous silicon photoreceptor 51;
A charging device 53 for charging the amorphous silicon photoconductor 51 to a predetermined potential;
A liquid developing device 18 for supplying the liquid developer 11 in which toner is dispersed in an insulating liquid to the amorphous silicon photoconductor 51, and a polishing device 58 for polishing the surface of the amorphous silicon photoconductor 51. This is a wet image forming method used.
2A to 2C, the surface of the amorphous silicon photosensitive member 51 is formed using a polishing apparatus 58 containing polishing particles 58a having a Mohs hardness in the range of 3 to 6 on the surface. It is characterized by including a polishing step.
Hereinafter, the wet image forming method using the wet image forming apparatus 10 of the first embodiment will be specifically described within a range not overlapping.

1. Rotational Speed As illustrated in FIGS. 2A to 2C, when the polishing apparatus 58 is a polishing roll, the rotational speed ratio (rotational speed ratio based on the rotational speed of the amorphous silicon photoreceptor) is − A value within the range of 50 to + 50% is preferable.
The reason for this is that when the rotation rate is less than −50%, the polishing effect on the surface of the amorphous silicon photosensitive member may be significantly reduced.
On the other hand, if the rotation rate exceeds + 50%, the polishing effect on the surface of the amorphous silicon photoreceptor may be excessively exhibited.
Therefore, it is more preferable to set the rotation speed rate to a value within the range of -30 to + 30%, and it is even more preferable to set the value within the range of -10 to + 10%.

2. Polishing frequency Further, the polishing process for the surface of the amorphous silicon photoreceptor by the polishing apparatus can be performed constantly, but it is also preferable that the polishing process is intermittently performed at predetermined intervals.
That is, when the degree of contamination of the surface of the amorphous silicon photoreceptor is severe, it is preferable to provide a dedicated cleaning mode as an exception.

In addition, it is preferable to carry out the polishing process in synchronization with a development process in which liquid development is performed to supply a liquid developer in which toner is dispersed in an insulating liquid.
In this case, it is preferable to set the predetermined interval for carrying out the polishing treatment step to a value within the range of 10 to 10,000 seconds.
This is because if the predetermined interval is less than 10 seconds, the polishing effect on the surface of the amorphous silicon photosensitive member may be excessively exhibited, or the polishing apparatus may be rapidly deteriorated.
On the other hand, if the predetermined interval exceeds 10,000 seconds, the polishing effect on the surface of the amorphous silicon photoconductor may be significantly reduced.
Therefore, the predetermined interval is more preferably set to a value within the range of 60 to 5000 seconds, and further preferably set to a value within the range of 500 to 3000 seconds.

[Example 1]
1. Preparation of polishing roller (1) Preparation of polishing layer solution Glass beads (Mohs hardness: 6, average particle size: 20 μm, outer shape: spherical) as polishing particles are added to 100 parts by weight of polyester polyol in a ball mill container. After adding so that it might become a ratio of 10 weight part, it mixed uniformly on conditions of room temperature, rotation speed 60rpm, and stirring time 10 hours.
Next, tolylene diisocyanate as a urethane curing agent was added to the ball mill container so as to have a ratio of 7 parts by weight to obtain a polishing layer solution.

(2) Application of polishing layer solution The obtained polishing layer solution was poured into a roller mold heated to 120 ° C and cured as it was for 20 hours.
That is, a polishing roll (diameter: 15 mm) in which a polishing layer having a thickness of 7 mm was formed on the surface and glass beads were present on the surface was obtained.

2. Evaluation of polishing roller (1) Filming resistance The obtained polishing roll was mounted on a wet image forming apparatus manufactured by Kyocera Mita, and filming resistance was evaluated under the following conditions.
That is, in a wet image forming apparatus (Kyocera Mita experimental machine) equipped with a developer tank, a drawing roller, a coating roller, a developing roller, a photoconductor having a diameter of 40 mm, and a polishing roller having a diameter of 15 mm, a linear velocity of 0.1 m / sec. A polishing roller was brought into contact with the photoconductor at a peripheral speed of + 10% and in a reverse rotation direction with a load of 1 kgf.
On the other hand, as a process condition, after continuously printing 50,000 predetermined image patterns on a white paper A4 with a developing bias of 300 V and a photoreceptor surface potential of 450 V, the printed state is visually observed to prevent filming. Sex was evaluated.
A: The occurrence of filming is not observed at all.
○: Little filming is observed.
Δ: A little filming is observed.
X: The occurrence of filming is remarkably observed.

(2) Durability of photoconductor After the evaluation of (1) filming resistance, a predetermined image pattern was printed on one A4 sheet, and the number of black spots was confirmed. That is, by polishing the surface of the photoconductor, the surface layer of the photoconductor is scraped, and as a result, the withstand voltage of the photoconductor is reduced, and the photoconductor layer of the photoconductor is insulated because it cannot withstand the charging electric field from the charging device. The phenomenon in which the charged charges cannot be retained and black spots are generated was evaluated according to the following criteria as the durability of the photoreceptor.
A: No black spot is generated.
○: The number of black spots is one.
Δ: The number of black spots generated is 2 to 4.
X: The number of black spots generated is 5 or more.

[Example 2]
In Example 2, a polishing roller was prepared and evaluated in the same manner as in Example 1 except that melamine resin powder (Mohs hardness: 4, average particle size: 10 μm, outer shape: polygon) was used as the abrasive particles. .

[Example 3]
In Example 3, a polishing roller was prepared and evaluated in the same manner as in Example 1 except that polyester resin powder (Mohs hardness: 3, average particle size 10 μm, outer shape: polygon) was used as the abrasive particles.

[Example 4]
In Example 4, melamine resin powder (Mohs hardness 4, average particle size 10 μm, outer shape: polygon) was used as abrasive particles, and it was adhered to the surface of the polishing roller prepared in Example 1 for evaluation. did.
However, in Example 4, a fibrous material having a diameter of 2 μm and a length of 3 mm was added to the polishing layer solution so as to be 1% by weight, and the configuration of the polishing roller shown in FIG. .

[Comparative Example 1]
In Comparative Example 1, a polishing roller was prepared and evaluated in the same manner as in Example 1 except that alumina (Mohs hardness: 12, average particle size: 1 μm, outer shape: spherical) was used as the abrasive particles.

[Comparative Example 2]
In Comparative Example 1, a polishing roller was prepared and evaluated in the same manner as in Example 1 except that silicon carbide (Mohs hardness: 13, average particle diameter: 1 μm, outer shape: spherical) was used as the abrasive particles.

[Comparative Example 3]
In Comparative Example 3, a polishing roller was prepared and evaluated in the same manner as in Example 1 except that boron oxide (Mohs hardness: 14, average particle diameter: 1 μm, outer shape: spherical) was used as the abrasive particles.

[Comparative Example 4]
In Comparative Example 4, a polishing roller was prepared and evaluated in the same manner as in Example 1 except that titanium oxide (Mohs hardness: 7, average particle diameter: 1 μm, outer shape: spherical) was used as the abrasive particles.

[Comparative Example 5]
In Comparative Example 5, a polishing roller was prepared and evaluated in the same manner as in Example 1 except that nylon particles (Mohs hardness: 2, average particle size: 10 μm, outer shape: polygon) were used as the abrasive particles.

According to the wet image forming apparatus and the wet image forming method using the wet image forming apparatus of the present invention, the wet image forming apparatus further includes a predetermined polishing apparatus for polishing the surface of the amorphous silicon photoconductor, and the surface of the polishing apparatus has Mohs hardness. By containing abrasive particles in the range of 3 to 6, it was possible to polish appropriately without damaging the surface of the amorphous silicon photoreceptor.
Therefore, the occurrence of filming is prevented over a long period of time, and excellent image characteristics can be stably obtained.
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. (A)-(c) is a figure provided in order to demonstrate the aspect of a grinding | polishing apparatus. 1 is a diagram provided for explaining a tandem wet color image forming apparatus equipped with a liquid developing device. FIG. It is a fragmentary sectional view provided in order to demonstrate an amorphous silicon photoconductor. It is a figure provided in order to demonstrate the dry-type image forming apparatus carrying the conventional grinding | polishing apparatus. It is a figure provided in order to demonstrate the structure of the conventional grinding | polishing apparatus.

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: developing roller (developer carrier)
13: Anilox roller 14: Pumping roller 15: Doctor blade 17: Charging device 18: Liquid developing device 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 32a: First cleaning means 32b: Second cleaning means 33: Cleaning blade 45: Liquid developer tank 46: Waste liquid tank 51: Photoreceptor drum 52: Static elimination device 53: Charging device 54: LED exposure device 57 : Cleaning blades 58, 58 ', 58 ", 58"': Polishing device (including polishing layer)
58a: abrasive particles 58b: base material 58c: core material 58d: fibrous substance 150: color printer (wet image forming apparatus)

Claims (9)

An amorphous silicon photoreceptor,
A charging device for charging the amorphous silicon photosensitive member to a predetermined potential;
A liquid developing device for supplying a liquid developer in which a toner is dispersed in an insulating liquid to the amorphous silicon photoreceptor;
A wet image forming apparatus comprising:
Further comprising a polishing apparatus for polishing the surface of the amorphous silicon photoreceptor,
A wet image forming apparatus comprising abrasive particles having a Mohs hardness in the range of 3 to 6 on the surface of the polishing apparatus.   The wet image forming apparatus according to claim 1, wherein the abrasive particles are exposed and exist on a surface of the polishing apparatus.   The wet image forming apparatus according to claim 1, wherein a polishing layer containing the abrasive particles is provided on a surface of the polishing apparatus.   The wet image forming apparatus according to claim 1, wherein the polishing apparatus is an elastic roller including a resin foam as a base material.   5. The wet image forming apparatus according to claim 1, wherein the abrasive particles are at least one selected from the group consisting of melamine resin powder, fluororesin powder, and glass beads. .   The wet image forming apparatus according to claim 1, wherein an outer shape of the abrasive particles is a polyhedral shape.   The wet image forming apparatus according to claim 1, wherein an average particle diameter of the abrasive particles is set to a value within a range of 0.001 to 100 μm.   The wet image according to any one of claims 1 to 7, wherein the content of the abrasive particles is set to a value in a range of 1 to 50% by weight with respect to the total amount of the polishing apparatus. Forming equipment. An amorphous silicon photoreceptor,
A charging device for charging the amorphous silicon photosensitive member to a predetermined potential;
A liquid developing device for supplying a liquid developer in which a toner is dispersed in an insulating liquid to the amorphous silicon photoreceptor;
A wet image forming method using a polishing apparatus for polishing the surface of the amorphous silicon photoreceptor,
A wet image forming method comprising a step of polishing the surface of the amorphous silicon photoreceptor using a polishing apparatus containing polishing particles having a Mohs hardness of 3 to 6 on the surface.

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