JP2002278295A - Coating roller for liquid developer, and liquid developing device and image forming device having the same coating roller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating roller which can make image quality stable by preventing a coating amount from decreasing as a liquid developer adheres. SOLUTION: In order to form a thin layer of the liquid developer on a developing roller 10 and develop a latent image on a photosensitive body 1 with the liquid developer forming the thin layer, an anilox roller 8 coats the developing roller 10 with the liquid developer held at an engraved part of the roller 8 while made to abut against the doctor blade 8 so that a specific amount of the liquid developer is held at the engraved part provided on the surface. Part or the whole of the engraved part is coated with amorphous fluororesin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an application roller used for applying a liquid developer in an image forming apparatus such as a wet electronic copying machine, and a liquid developing apparatus and an image forming apparatus provided with the applying roller.

[0002]

2. Description of the Related Art In a liquid developing apparatus, an electrostatic latent image formed on a photoreceptor is developed with a liquid developer in which a toner is dispersed in an insulating liquid. The electrostatic latent image is developed by moving the charged toner in the insulating liquid by the force of static electricity. Therefore, the shorter the moving distance, the higher the developing efficiency. For this purpose, it is necessary to form a thin layer of liquid developer on a developing roller in a micrometer unit (micron unit), and to contact the photoreceptor with the thinned liquid developer for development. Is particularly remarkable when a high-viscosity liquid developer of 50 to 10,000 mPa · s is used.

In order to form such a thin layer of liquid developer, for example, an application roller (anilox roller: see FIG. 2) whose surface is regularly engraved is brought into contact with the development roller, and The liquid developer is supplied to the surface, and a measuring member (doctor blade) is brought into contact with the surface, whereby the amount of the liquid developer on the surface of the application roller is measured and transferred to the developing roller.

[0004]

When the liquid developer is applied to the developing roller so as to make it thinner as described above, and the development is performed, the thickness of the layer determines the density of the image. It is extremely important to form a thin layer having a uniform thickness.

On the other hand, after forming an engraved portion on the surface of a roller made of carbon steel (S25C), hard chrome plating for surface protection is performed to produce an anilox roller, and printing is repeated using this anilox roller. When the amount of liquid developer applied to the developing roller was examined, it was found that the amount of the liquid developer decreased to some extent in the initial stage, as shown by the solid line in FIG. 4, and then gradually decreased with use. did.
The decrease in the initial stage is considered to be due to the aging of the anilox roller and the doctor blade.
Regarding the subsequent decrease, when the anilox roller is cleaned, the coating amount returns to the amount at the time of the initial stage as shown by the broken line in the same figure, so that the liquid developer adheres and remains on the engraved portion of the anilox roller. It is thought to have occurred.

[0006] Such a decrease in the amount of coating means that the layer of the liquid developer formed on the developing roller becomes thinner with time, which undesirably lowers the image density in the long term.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an application roller capable of preventing a decrease in the application amount due to the adhesion of a liquid developer and providing a stable image quality. It is another object of the present invention to provide a liquid developing apparatus and an image forming apparatus having the coating roller.

[0008]

In order to solve the above-mentioned problems, the invention according to claim 1 is to form a thin layer of a liquid developer on a liquid developer carrier and use the liquid developer forming the thin layer. In order to develop the latent image, the liquid developer held in the engraved portion while the liquid developer held in the engraved portion is brought into contact with the measuring member so that a predetermined amount of the liquid developer is held in the engraved portion provided on the surface. A roller for applying a liquid developer to be applied on a carrier, wherein a part or the entirety of the engraved portion is coated with an amorphous fluororesin.

According to a second aspect of the present invention, in the liquid developer application roller according to the first aspect, a part or all of the engraved portion is made of an inorganic oxide or an aggressive surface oxidation treatment other than being left at room temperature. The amorphous fluororesin is a liquid phase at a temperature range of 0 ° C. to 70 ° C. and has at least one hydrolyzable functional group, A part or all of the part and the amorphous fluororesin are bonded via oxygen of a material constituting part or all of the engraved part.

According to a third aspect of the present invention, in the liquid developer application roller according to the second aspect, the amorphous fluororesin has an alcohol group or an alkoxy group as the hydrolyzable functional group. It is characterized by.

According to a fourth aspect of the present invention, in the liquid developer application roller according to the third aspect, the amorphous fluororesin has a methoxy group or an ethoxy group as the alkoxy group. .

According to a fifth aspect of the present invention, in the liquid developer application roller according to the second aspect, the amorphous fluororesin has a silanol group or an alkoxysilane group as the hydrolyzable functional group. It is characterized by the following.

According to a sixth aspect of the present invention, in the liquid developer application roller according to the fifth aspect, the amorphous fluororesin has a methoxysilane group or an ethoxysilane group as the alkoxysilane group. Features.

According to a seventh aspect of the present invention, in the liquid developer application roller according to the second aspect, the amorphous fluororesin has a carboxylic group or an ester group as the hydrolyzable functional group. It is characterized by.

According to an eighth aspect of the present invention, in the liquid developer application roller according to the seventh aspect, the amorphous fluororesin has a methyl carbonate group or an ethyl carbonate group as the ester group. It is characterized by.

According to a ninth aspect of the present invention, in the liquid developer application roller according to any one of the second to eighth aspects, the amorphous fluororesin has a main chain of perfluoropolyether. Is used.

According to a tenth aspect of the present invention, in the liquid developer application roller according to any one of the third to sixth aspects, the amorphous fluororesin has a main chain comprising perfluoropolyether. A methylene group in which at least one hydrogen is substituted with bromine or iodine is present between the hydrolyzable functional group and the main chain.

The invention according to claim 11 is the liquid developer application roller according to claim 9 or 10, wherein a part or all of the engraved portion is coated with the amorphous fluororesin. It is characterized by being manufactured by being left in an environment of 50 ° C. or more and 250 ° C. or less for 15 minutes or more.

According to a twelfth aspect of the present invention, in the liquid developer application roller according to the eleventh aspect, after coating a part or the entirety of the engraved portion with the amorphous fluororesin, the temperature is not less than 80 ° C. It is characterized by being manufactured by being left for 30 minutes or more in an environment of not more than ℃.

According to a thirteenth aspect of the present invention, there is provided a liquid developing apparatus having the liquid developer applying roller according to any one of the first to twelfth aspects.

According to a fourteenth aspect of the present invention, there is provided an image forming apparatus comprising: the liquid developer applying roller according to any one of the first to twelfth aspects; and an amorphous silicon photosensitive member that carries the latent image. It is characterized by.

According to any one of the first to twelfth aspects of the present invention, since part or all of the engraved portion is coated with an amorphous fluororesin, the liquid developer adheres to the engraved portion. Thus, it is possible to prevent a decrease in the coating amount caused by the above, and to maintain a constant image density over a long period of time, thereby obtaining a stable image quality.

In particular, according to the invention as set forth in any one of claims 2 to 12, a part or the whole of the engraved portion is made of an inorganic oxide or an inorganic material or an organic material which has been subjected to an active surface oxidation treatment other than standing at room temperature. The amorphous fluororesin is a liquid phase at a temperature range of 0 ° C. to 70 ° C. and has at least one hydrolyzable functional group. Is bonded via the oxygen of the material constituting part or all of the engraved part, so that the coating layer formed by the fluororesin is prevented from peeling, or even if peeling occurs, its expansion Can be prevented or the recovery can be achieved, and a decrease in the function of the coating layer due to peeling can be suppressed.

According to the ninth aspect, perfluoropolyether is used for the main chain of the fluororesin,
Since an alcohol group or the like is used as a hydrolyzable functional group, the main chain is partially strongly adhered to the engraved portion, and sufficient durability of the coating layer against the contact force of the measuring member can be secured. it can. This is claimed in claim 10
This is particularly remarkable when a methylene group in which at least one hydrogen is substituted with bromine or iodine is interposed between the hydrolyzable functional group and the main chain as in the invention according to (1).

Further, according to the present invention, after the coating roller coats a part or the entirety of the engraved portion with the amorphous fluororesin, the coating roller is heated to 50 ° C. or higher.
Since it is manufactured by leaving it in an environment of 0 ° C or less for 15 minutes or more, it is necessary to secure the durability of the coating layer against the contact force of the measuring member by strengthening the chemical bonding of the fluororesin to the engraved part. Can be.

According to the thirteenth and fourteenth aspects of the present invention, the application roller according to any one of the first to twelfth aspects is used, so that the first to the first aspects are used.
2 can obtain the effect of the invention according to any one of (2) and (14) in the invention according to claim 14, since the latent image carrier for carrying the latent image is an amorphous silicon photoconductor,
The amorphous silicon photoreceptor and the application roller can work together to stabilize the image quality for a long time.

[0027]

Embodiments of the present invention will be described with reference to the drawings.

[First Embodiment] FIG. 1 shows a schematic configuration of a main part of an electrophotographic copying machine as an image forming apparatus according to the present invention. In this copying machine, a charger 2, an exposure device (not shown), a liquid developing device 3, a transfer device 4, and a cleaning device 5 are arranged around a photoreceptor 1.

The photosensitive member 1 is rotated in the direction of arrow A by a driving means such as a motor (not shown).
i, OPC, etc. can be used. Here, a-Si (amorphous silicon) is used, which has high durability and can stabilize image quality for a long time in combination with an anilox roller described later. Such a photoreceptor does not necessarily need to take the form of a roller, but may be an endless belt.

The charger 2 charges the surface of the photoreceptor 1, and may be a charger type as shown in the figure or a roller type. The exposure device is located immediately after the charger 2 along the rotation direction of the photoconductor 1, and forms an electrostatic latent image on the surface of the photoconductor 1. As such an exposure apparatus, an LED, a laser scanning optical system, or the like can be used.

The liquid developing device 3 is provided behind the charger 2 along the rotation direction of the photosensitive member 1 and forms a toner image corresponding to the electrostatic latent image on the surface of the photosensitive member 1. The liquid developing device 3 includes a developer accommodating tank 6, stirring / conveying screws 7, 7, and an anilox roller 8 as a coating roller.
, A doctor blade 9 as a measuring member, a developing roller 10 as a liquid developer carrier, a cleaning blade 11, a sweep roller 12, and a cleaning blade 13.

The developer storage tank 6 has a supply section 6a for storing the developer used for development and a return section 6b for storing the used developer. This developer storage tank 6
Is a low-viscosity (about 1 × 10 ⁻⁶ m ² / s (1 cSt)) and low-concentration (using Isopar (trademark: Exxon)) which is conventionally commercially available and used as a carrier. The liquid developer is not a liquid developer (about 1%) but a high-viscosity, high-concentration liquid developer. Its kinematic viscosity and concentration are, for example, 5 × 10 ⁻⁵ m ² / s (50 cS).
t) to 5 × 10 ⁻³ m ² / s (5000 cSt), and the concentration is preferably in the range of about 5% to 40%. As the carrier liquid, those having high insulating properties such as silicone oil, normal paraffin, IsoparM (trademark: Exxon), vegetable oil or mineral oil are used, and the volatility and non-volatility are selected according to the purpose. Further, the particle size of the toner is preferably within a range from so-called submicron to about 6 μm, and may be selected according to the purpose.

The agitating / transporting screws 7, 7 are immersed in the developer housed in the supply section 6a, and are immersed in arrows B ₁ ,
Is rotatable in a B ₂ direction, the bottom of the anilox roller 8 is immersed in the developer contained in the supply unit 6a.

The anilox roller 8 is obtained by transferring an engraving pattern to the outer peripheral surface of a columnar member made of relatively soft carbon steel (S25C), applying hard chrome plating to the surface to prevent abrasion, and further applying a surface. It is manufactured by coating an amorphous fluororesin on the substrate. here,
On the surface of the anilox roller 8, as shown in FIG.
Are uniformly provided as engraved portions, and the grooves 8a are formed in an inclined shape so as to secure a sufficient application amount even for a highly viscous liquid. On the surface of the anilox roller 8, instead of the groove 8a, for example, an inverted pyramid-shaped concave portion 8b is provided as shown in FIG.
As shown in FIG. 7, a lattice-shaped recess 8c may be provided.

The anilox roller 8 contacts the developing roller 10 and rotates in the direction of arrow C. The anilox roller 8 contacts the doctor blade 9 at a position behind the supply unit 6a and in front of the developing roller 10 along the direction of rotation. Touched. The developing roller 10 comes into contact with the photoreceptor 1 and the arrow D
, And is in contact with the cleaning blade 11 at a position behind the photoreceptor 1 and in front of the anilox roller 8 along the rotation direction. Sweep roller 1
2 is a photoconductor 1 at a position behind the developing roller 10.
, And rotates in the direction of arrow E, and the cleaning blade 13 is in contact with the sweep roller 12.

Developing roller 10 and sweep roller 12
Is provided with a layer of a conductive elastic body on the outer periphery thereof, and its surface is coated or covered with a tube, and has a smoothness of Rz = 3 μm or less. Urethane rubber can be used for these elastic layers, and the rubber hardness of each elastic layer is desirably 50 degrees or less in JIS-A hardness. However, the material of each elastic layer is not limited to urethane rubber, and any other material may be used as long as it has conductivity and does not swell or dissolve in the developer / carrier liquid. Is also good. Further, the developing roller 10 and the sweep roller 12 are made of a material which has conductivity and is not swelled or dissolved by the developer / carrier liquid, and furthermore, the inner layer does not come into contact with the developer / carrier liquid. In this case, the material of the inner layer portion is not restricted by conductivity and swelling / dissolving, and only needs to have appropriate elasticity. At this time, the developing bias voltage and the sweep bias voltage applied to the developing roller 10 and the sweep roller 12 need to be applied not from the central axis of the developing roller 10 and the sweep roller 12 but from the surface.

The elastic layer may be provided not on the developing roller 10 and the sweep roller 12 but on the photosensitive member side as described above. The cleaning blade 11 and the cleaning blade 13 may be metal blades or rubber blades. Alternatively, a cleaning roller may be provided instead of the cleaning blade 11 or the cleaning blade 13.

The transfer device 4 has a transfer roller 14 and a transfer belt 15, and transfers the toner image formed on the photoconductor 1 to the transfer belt 15 by the transfer roller 14. The cleaning device 5 includes a discharging lamp 16 and a cleaning blade 17.
6 removes the charge on the photoconductor 1 and removes the toner remaining on the photoconductor 1 with the cleaning blade 17.

In order to form an image by reversal development in the copying machine according to this embodiment, first, the surface of the photosensitive member 1 rotating at a constant speed in the direction of arrow A is uniformly charged by the charger 2 in the dark. Then, a light image of the original is irradiated and formed on the surface by exposure L from an exposure device to form an electrostatic latent image. continue,
Toner is attached to the electrostatic latent image by the liquid developing device 3 to perform development, and the developed toner image is transferred to the transfer belt 15 in the transfer device 4, and the toner image transferred to the transfer belt 15 is not shown. The image is transferred to a recording medium such as transfer paper in a secondary transfer device. After the recording medium is fixed in a fixing device (not shown), the recording medium is discharged out of the copying machine. On the other hand, the photoconductor 1 is neutralized and cleaned by the cleaning device 5 to prepare for the next image forming operation.

As a transfer method in the transfer device, any of a method using corona discharge, a method using an electrostatic roller, an adhesive transfer method, a thermal transfer method, and the like may be used. Solvent fixing method,
Any of a UV fixing method, a pressure fixing method, and the like may be used.

Here, the liquid developing device 3 will be described in detail. The developing roller 10 and the sweep roller 12 are
By contacting them with appropriate pressure against
The elastic layers of the developing roller 10 and the sweep roller 12 are elastically deformed to form a developing nip and a removing nip.
In particular, by forming the development nip, it is possible to secure a certain development time for the toner in the developer to move and adhere to the photoconductor 1 by the development electric field in the development area. Further, by adjusting the contact pressure between the developing roller 10, the sweep roller 12 and the photosensitive member 1, the nip width at each nip portion (the width in the surface movement direction of the photosensitive member 1) can be adjusted. Is set to be equal to or larger than the product of the linear speed of the developing roller 10 and the development time constant. Here, the “development time constant” is a time required until the amount of the developer is saturated, and is obtained by dividing a nip width by a process speed. For example, if the nip width is 3 mm and the process speed is 300 mm / s, the development time constant is 1
0 ms.

A thin layer of developer is formed on the surface of the developing roller 10 by the anilox roller 8 during development. That is, the developer in the supply portion 6a of the developer storage tank 6 is supplied to the outer peripheral surface (engraving portion) of the anilox roller 8 by the help of the rotation of the stirring / transferring screws 7, 7, and the excess development is performed. The developer is scraped off by the doctor blade 9 to measure the developer, and a predetermined amount of the developer is applied to the surface of the developing roller 10. Here, the developing roller 1
The coating thickness of the developer is set to 3 to 10 μm so that the content of the pigment in the toner carried per 1 cm ² of the surface of No. 0 is 3 μg to 60 μg. The reason for this is that if the coating thickness is such that the pigment content in the toner carried per 1 cm ² of the surface of the developing roller 10 is smaller than 3 μg, the image portion of the latent image formed on the photoreceptor 1 (toner A sufficient amount of pigment does not move to
This is because the image density of the image portion may be reduced.
In addition, when the coating thickness is such that the pigment content is greater than 60 μg, the excess toner remaining on the background portion after development (non-image portion: a portion where toner should not adhere) increases.
This is because even if the sweep roller 12 sweeps as described later, the removal may be incomplete.

When the thin layer of the developer formed on the surface of the developing roller 10 passes through the position where the developing nip is formed (the contact position between the developing roller 10 and the photosensitive member 1), Provide for development according to the latent image above. That is, at the time of the passage, the toner moves to the surface of the photoreceptor 1 in the image portion, and in the background portion, the toner moves to the surface of the developing roller 10 by the electric field formed by the developing bias potential and the photoreceptor potential. The toner does not adhere to the background. However, if a part of the toner in the thin layer in contact with the background portion in the nip portion is not completely moved to the surface of the developing roller 10 and remains on the photosensitive member 1, so-called fog is caused. Therefore, while the surface of the sweep roller 12 moves at substantially the same speed as the surface of the photoconductor 1, the toner (fog toner) causing the fog is swept (cleaned).
I do.

As described in the description of the prior art, in such an image forming apparatus, the image density is determined by the thickness of the liquid developer applied to the developing roller. That is, when the amount of the liquid developer applied on the developing roller changes, the image density changes, and the applied amount mainly depends on the volume of the engraved portion (in this example, the groove 8a) formed on the surface of the anilox roller. Capacity) and the speed ratio between the anilox roller and the developing roller. As described above, in the conventional anilox roller, the coating amount gradually decreased and the image density also decreased, but this was because the critical surface tension of the surface of the anilox roller was large, This is because the liquid developer gradually adheres to the surface of the anilox roller due to the pressure acting on the liquid developer between the doctor blade and the like, and as a result, the volume of the engraved portion decreases and the application amount decreases.

On the other hand, the anilox roller 8 in the present embodiment has a surface coated with an amorphous fluororesin,
The critical surface tension of the surface is 25 mN / m or less. Thereby, the adhesion of the liquid developer is prevented, and a decrease in the application amount due to the adhesion can be prevented. In addition, since the surface treatment can realize a thin film coating by using an amorphous fluororesin,
This is possible without impairing the precision of the fine engraving pattern of the anilox roller 8. Examples of the surface treatment agent for this include Cytop (trade name: Asahi Glass Co., Ltd.) and Teflon AF (trade name: Dupont), which are often used as heterocyclic amorphous fluororesins.

The following effects were also obtained by coating the surface of the anilox roller 8 with an amorphous fluororesin.

The non-engraved portion (groove 8a) of the anilox roller 8
Liquid developer physically adhering to the non-image areas (areas not involved in image formation) on the developing roller 10 was reduced.

Since the frictional resistance of the surface of the anilox roller 8 is reduced by coating with a fluorine-based resin, the anilox roller 8 itself, the doctor blade 9,
The service life of the developing roller 10 and the like can be extended.

The shaft of the anilox roller 8 is sealed by a sealing material (not shown) in order to prevent the liquid developer from transmitting and leaking. No adhesion was observed, so that the generation of the leakage could be suppressed, and the frictional resistance did not increase, so that the durability of the sealing material could be improved.

[Second Embodiment] As described in the first embodiment, by coating the engraved portion with an amorphous fluororesin, it is possible to prevent a decrease in the applied amount of the liquid developer over time. However, if the adhesion of the coating to the engraved portion is weak, the coating will peel off due to the contact force (sliding contact) of the doctor blade 9 or the like. For example, in the anilox roller 8 according to the first embodiment, the coating layer functions until a certain point in time. However, when a severe durability test is performed, widespread peeling occurs and the liquid developer adheres. This is because the glass transition temperature of the fluororesin is 1
Since the temperature is higher than 00 ° C. and higher than the temperature range usually used in the image forming apparatus, the coated resin is a solid phase and functions as a film in an actual use state. And, once peeling occurs in a part of the coating, this leads to large-scale peeling.

Therefore, in the present embodiment, the engraved portion (surface) is oxidized by aggressive means, and is in a liquid phase in a temperature range usually used, that is, in a temperature range of 0 ° C. to 70 ° C., and The coating is performed using an amorphous fluororesin having at least one functional group capable of binding to the engraved portion by hydrolysis and capable of being chemically modified.

As a result, the hydrolyzable group provided on a part of the fluororesin is strongly bonded to the oxidized engraved portion by an aggressive means, so that the thin film coating and the abrasion resistance are simultaneously achieved. Further, by making the fluororesin a liquid phase in a temperature range of 0 ° C. to 70 ° C., even if partial exfoliation occurs, the fluororesin can be moved by sliding contact of the doctor blade 9, so that the exfoliated portion is again formed. It is possible to allow the fluororesin to be present so as to cover, and it is possible to prevent the peeled surface from expanding, which is a problem with the solid fluororesin.

Here, it is desirable to use an amorphous fluororesin having a perfluoropolyether structure as a main chain. Even if a perfluoropolyether structure is provided with a functional group that chemically bonds to the surface of the engraved part at its end, the main chain exists so as to be horizontal to the roller surface. Since it is known that it easily rotates around the center, it is possible to quickly cover the peeling region partially generated by the sliding contact of the doctor blade 9. On the other hand, in the case of fluoroalkylsilane or the like, only the silane structure region side faces the roller surface like the micellar structure and easily rises perpendicular to the roller surface, so that once the separation occurs, the separation region hardly recovers.

The hydrolyzable functional group may be an alcohol group or an alkoxy group having a group directly hydrolyzed to carbon, or a silanol group, an alkoxysilane group, a carboxylic group or an ester group. However, in order to easily cause hydrolysis, the group to be hydrolyzed is an OH group, a methoxy group, a low-molecular-weight alkoxy group of about ethoxy group, a methoxysilane group, a low-molecular-weight alkoxysilane group of about ethoxysilane group, or methyl. It is desirable that the ester group be a low molecular weight ester group such as a carbonate group or an ethyl carbonate group.

In order to further promote the hydrolysis, a main chain is provided between a group that hydrolyzes a methylene group in which at least one hydrogen is substituted by a halogen atom having a high electron density such as iodine or bromine and the like. The presence is effective because the oxygen radicals are stabilized.

[0056]

EXAMPLE In this example, after engraving an engraving pattern (pattern of the groove 8a) on the outer peripheral surface of a roller made of S25C, which is a relatively soft carbon steel, in order to prevent surface wear. An anilox roller 8 was manufactured by performing hard chrome plating to form an engraved portion and further performing the following surface treatment. That is, an organic fluorine-containing polymer containing silicon is diluted with a suitable perfluorocarbon as a solvent, and this is spray-coated on the engraved portion.
The hydrolysis reaction was completed by leaving the substrate in an environment of 0 ° C. or more and 250 ° C. or less for at least 15 minutes or more to obtain a surface treatment. However,
If the temperature is higher than 200 ° C., there is a concern that the fluorine material itself may be decomposed. Therefore, it is preferable that the fluorine material be left in an environment of 80 ° C. to 200 ° C. for 30 minutes or longer. The thickness of the coating layer formed here was 10 nm or less, but if the thickness of the coating layer is 1 nm or more, the effect as a liquid phase resin for partial peeling, that is, a recovery function for a peeled area is obtained. be able to.

As a result of repeating the printing using the anilox roller 8 and measuring the change in the coating amount, as shown in FIG. 5 as "with surface treatment", the coating amount hardly changes even if the number of printings increases. Good result was obtained.

The present invention is not limited to the above-described embodiment. For example, the engraved portion may be made of an oxide ceramic material mainly composed of zirconium oxide or aluminum oxide. This makes it possible to firmly bond the amorphous fluororesin having a hydrolyzable functional group to the engraved portion without performing a special oxidation treatment, and obtain sufficient durability against sliding contact of the doctor blade. be able to.

The fluororesin may be coated by dip coating, roll coating, or the like, and the diluting solvent may be perfluorohexane, perfluoromethylcyclohexane, perfluoro-1,3-dimethylcyclohexane, dichlorobenzene. Pentafluoropropane or the like can be used.

[0060]

As described above, according to any one of the first to twelfth aspects of the present invention, a part or the whole of the engraved portion is coated with an amorphous fluororesin, so It is possible to prevent a decrease in the coating amount due to the adhesion of the liquid developer to the portion, and to maintain a constant image density over a long period of time, thereby obtaining a stable image quality.

In particular, according to the invention of any one of claims 2 to 12, part or all of the engraved portion is made of an inorganic oxide or an inorganic material or an organic material which has been subjected to an active surface oxidation treatment other than being left at room temperature. The amorphous fluororesin is a liquid phase at a temperature range of 0 ° C. to 70 ° C. and has at least one hydrolyzable functional group. Is bonded via the oxygen of the material constituting part or all of the engraved part, so that the coating layer formed by the fluororesin is prevented from peeling, or even if peeling occurs, its expansion Can be prevented or the recovery can be achieved, and a decrease in the function of the coating layer due to peeling can be suppressed.

According to the ninth aspect, perfluoropolyether is used in the main chain of the fluororesin,
Since an alcohol group or the like is used as a hydrolyzable functional group, the main chain is partially strongly adhered to the engraved portion, and sufficient durability of the coating layer against the contact force of the measuring member can be secured. it can. This is claimed in claim 10
This is particularly remarkable when a methylene group in which at least one hydrogen is substituted with bromine or iodine is interposed between the hydrolyzable functional group and the main chain as in the invention according to (1).

Further, according to the present invention, after the coating roller coats a part or the whole of the engraved portion with an amorphous fluororesin, the coating roller is heated to 50 ° C.
Since it is manufactured by leaving it in an environment of 0 ° C or less for 15 minutes or more, it is necessary to secure the durability of the coating layer against the contact force of the measuring member by strengthening the chemical bonding of the fluororesin to the engraved part. Can be.

According to the invention according to claim 13 or claim 14, the application roller according to any one of claims 1 to 12 is used, so that the application roller according to claim 1 is used.
2 can obtain the effect of the invention according to any one of (2) and (14) in the invention according to claim 14, since the latent image carrier for carrying the latent image is an amorphous silicon photoconductor,
The amorphous silicon photoreceptor and the application roller can work together to stabilize the image quality for a long time.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a schematic configuration of a main part of an image forming apparatus according to the present invention.

FIG. 2 is an explanatory view showing an anilox roller of the image forming apparatus of FIG. 1;

FIG. 3 shows another example of the engraving part of the anilox roller,
(A) is an explanatory diagram showing a case where the engraved portion is an inverted pyramid type, and (b) is a diagram showing a case where the engraved portion is a lattice type.

FIG. 4 is an explanatory diagram showing a change in an application amount by a conventional anilox roller.

FIG. 5 is an explanatory diagram showing a change in the application amount of the anilox roller according to the present invention, as compared with a conventional anilox roller.

[Explanation of symbols]

 3 Liquid Developing Device 8 Anilox Roller (Coating Roller) 9 Doctor Blade (Lightweight Member) 10 Developing Roller (Liquid Developer Carrier)

Claims (14)

[Claims] 1. A method for forming a thin layer of a liquid developer on a liquid developer carrier and developing a latent image with the liquid developer forming the thin layer, a predetermined amount of an engraved portion provided on the surface. A liquid developer application roller for applying the liquid developer held in the engraved portion on the liquid developer carrier while being in contact with the measuring member so that the liquid developer is held; A part or the whole of which is coated with an amorphous fluorine resin. 2. The liquid developer application roller according to claim 1, wherein a part or the whole of the engraved portion is made of an inorganic oxide or an inorganic material or an organic material which has been subjected to an active surface oxidation treatment other than standing at room temperature. The amorphous fluororesin is in a liquid phase at a temperature range of 0 ° C. to 70 ° C. and has at least one hydrolyzable functional group; A liquid developer application roller, wherein the amorphous fluorine resin and the amorphous fluorine resin are bonded via oxygen of a material constituting part or all of the engraved portion. 3. The liquid developer applying roller according to claim 2, wherein the amorphous fluororesin has an alcohol group or an alkoxy group as the hydrolyzable functional group. Roller for applying agent. 4. The liquid developer application roller according to claim 3, wherein the amorphous fluororesin has a methoxy group or an ethoxy group as the alkoxy group. . 5. The liquid developer applying roller according to claim 2, wherein the amorphous fluororesin has a silanol group or an alkoxysilane group as the hydrolyzable functional group. Application roller for developer. 6. The liquid developer applying roller according to claim 5, wherein the amorphous fluororesin has a methoxysilane group or an ethoxysilane group as the alkoxysilane group. Application roller. 7. The liquid developer applying roller according to claim 2, wherein the amorphous fluororesin has a carboxylic group or an ester group as the hydrolyzable functional group. Roller for applying agent. 8. The liquid developer applying roller according to claim 7, wherein the amorphous fluororesin has a methyl carbonate group or an ethyl carbonate group as the ester group. Roller for applying agent. 9. The liquid developer applying roller according to claim 2, wherein the amorphous fluororesin has perfluoropolyether in a main chain thereof. A roller for applying a liquid developer. 10. The liquid developer application roller according to claim 3, wherein the amorphous fluororesin is made of perfluoropolyether in a main chain, and the hydrolysis is carried out. A liquid developer application roller, characterized in that a methylene group in which at least one hydrogen has been replaced by bromine or iodine exists between a possible functional group and the main chain. 11. The liquid developer applying roller according to claim 9, wherein a part or the whole of the engraved portion is coated with the amorphous fluororesin, and then 50 ° C. or more and 250 ° C. or less. A liquid developer application roller manufactured by being left to stand for 15 minutes or more in the above environment. 12. The liquid developer application roller according to claim 11, wherein a part or the entirety of the engraved portion is coated with the amorphous fluororesin, and then the coating is performed in an environment of 80 ° C. or more and 200 ° C. or less. A roller for applying a liquid developer, which is manufactured by being left for 30 minutes or more. 13. A liquid developing apparatus comprising the liquid developer applying roller according to claim 1. Description: 14. An image forming apparatus comprising: the roller for applying a liquid developer according to claim 1; and an amorphous silicon photoreceptor carrying the latent image.