JP4672890B2 - Image forming apparatus and method for oxidizing surface of developer carrier - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an image forming apparatus such as an electrophotographic copying machine, a printer, and a facsimile machine using a developer carrier and, more particularly, at least a high-viscosity and high-concentration liquid developer in which toner is dispersed in a carrier liquid. The present invention relates to an image forming apparatus having one developer carrier and developing a latent image formed on the latent image carrier with the liquid developer carried on the developer carrier.
[0002]
[Prior art]
Conventionally, there has been a problem of toner filming on the developer carrying member. As a result, the developing bias voltage may not be normally applied, and problems such as a decrease in image density and an increase in non-image area density occur. As countermeasures, there have been methods of using fluororesins such as PTFE, PVdF, and PFA as the material of the surface layer, and coating the surface layer with these fluororesins.
[0003]
However, when a fluororesin is used as a material, the strength of the material itself is low and easily scratched, and the conventional fluorine coat has a problem that the coat has a weak adhesive force to the substrate and the coat is easily peeled off.
[0004]
[Problems to be solved by the invention]
These conventional methods have the following problems. The first problem is that as the printing characteristics become more precise and faster, there is an increasing need for higher precision of rollers, and it is necessary to increase the precision of surface roughness, roller diameter, flare, etc. It is a point. Variations in roller diameter and flares will result in variations in linear speed, which may cause the minute dots to collapse, impede contact with the application roller, and the surface roughness will affect the developability of fine dots and the smoothness of the image. It is.
The second problem is that it is essential that the fluorine-based material that is present on the surface of a developing roller or the like as a developer carrier has friction resistance. The developing roller needs to scrape off the developer remaining on the roller once after development, and it is necessary to always contact the cleaning of the blade or the like. Further, in order to apply the developer, an anilox roller having irregularities may be brought into contact therewith.
[0005]
One solution to the first problem is to reduce the thickness of the fluorine-based material. The eutectoid plating has a limit in terms of thinning, and a method using a dry process is most suitable for thinning. However, in most of the dry processes, a thin film having a maximum thickness of 0.1 μm is only physically attached on the base material of the developing roller, and the second problem of friction resistance cannot be solved. As for a method using a wet process, a crystalline material such as PTFE cannot cope with thinning, and such an amorphous fluororesin material is basically physically attached. Can't meet the challenges.
[0006]
The optimal solution to these problems is to chemically modify the fluorine-based material, and to aggressively optimize the substrate of the developing roller so as to have a strong chemical bond.
[0007]
Further, as a third problem, it is essential to prevent a part of the peeling between the fluorine-based material and the developer carrier from expanding to a large-scale peeling. When Teflon AF (trade name, manufactured by DuPont), which has been conventionally used as a heterocyclic amorphous fluororesin, is actually tested for durability against friction, partial coating peeling of the resin is extremely difficult. It expanded in a short time and became a large-scale exfoliation. This is because the glass transition temperature of the above amorphous fluororesin is 100 ° C. or higher, which is sufficiently higher than a practical temperature range used as an image forming apparatus such as a copying machine or a printer, and is coated in an actual use state. This resin originates from the fact that it is a solid phase and functions as a film. Since it is film-like, partial peeling is not only due to exposure of the material surface of the developing roller, which increases the surface energy of the peeling part, but also because the interface between the substrate of the developing roller and the fluorine material is exposed. Accelerates peeling.
[0008]
[Means for Solving the Problems]
The present invention solves the above-described problems. In an image forming apparatus, a base material whose surface is oxidized by aggressive means is used, and at least the surface is usually used as an image forming apparatus such as a copying machine or a printer. An amorphous fluororesin that is in a liquid phase exists in a temperature range to be used, that is, a temperature range of 0 to 70 ° C., and the resin partly bonds with the base material of the developer carrier by hydrolysis. The material is characterized by having at least one functional group capable of being chemically modified.
[0009]
That is, thin film coating is achieved by using an amorphous fluororesin. Thin film coating and improved friction resistance can be achieved at the same time by hydrolyzable groups provided on a part of the fluororesin strongly bonding to the surface of the developer carrier whose surface has been oxidized by aggressive means. Is done. Furthermore, by setting the liquid phase in the temperature range of 0 to 70 ° C., even if partial peeling occurs, the fluororesin moves due to friction caused by a cleaning member, a coating member, etc., and covers the peeling surface again. Therefore, it is possible to prevent the spread of the peeling surface, which is a problem with solid phase fluororesin.
[0010]
As a material of the amorphous fluororesin, it is desirable to use an amorphous fluororesin having a perfluoropolyether structure as a main chain. The perfluoropolyether structure has a functional group that chemically bonds to the base of the developer carrier at the end, so that the main chain is horizontal to the base of the developer carrier and can be developed even at room temperature. It is known to easily rotate around a functional group bonded to the base material of the agent carrier. Since it has such characteristics, it is possible to quickly cover the peeled area partially generated by friction caused by a cleaning member, an application member, or the like.
[0011]
On the other hand, in the fluoroalkyl silane, etc., only the silane structure region side is opposed to the base material of the developer carrying body and has a structure that stands up perpendicularly to the base material of the developer carrying body. When peeling occurs, recovery to the peeling region hardly occurs.
[0012]
The functional group that causes hydrolysis may be an alcohol group or an alkoxy group to which a group that directly hydrolyzes carbon is bonded, or may be an alkoxysilane group, a silanol group, a carboxylic acid group, or an ester group. However, in order to facilitate hydrolysis, the hydrolyzing group is preferably a low molecular weight alkoxy group such as an OH group, a methoxy group, or an ethoxy group.
[0013]
In order to further promote the hydrolysis, it is possible to make oxygen radicals exist by substituting at least one hydrogen with a halogen atom having a high electron density such as iodine or bromine between the hydrolyzing group and the main chain. It is effective because it stabilizes.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an example of an embodiment in which the present invention is applied to an electrophotographic copying machine (hereinafter referred to as a copying machine) which is a liquid development image forming apparatus will be described. FIG. 1 is a schematic configuration diagram of a main part of a copying machine according to the present embodiment. In the copying machine according to the present embodiment, a charging device 2, an exposure device 3, a developing device 4, a transfer roller 5, a cleaning device 6 and the like are disposed around a photosensitive drum 1 as a latent image carrier. The material of the photosensitive drum 1 can be a-Si, OPC or the like, the charging device 2 can be in the form of a roller or a charger, and the exposure device 3 can be an LED or a laser scanning optical system. .
[0015]
A case where an image is formed by reversal development with the copying machine having the above configuration will be described. The photosensitive drum 1 is rotationally driven in the direction of the arrow at a constant speed during copying by a driving means such as a motor (not shown). Then, after being uniformly charged to about 600 V in the dark by the charging device 2, a light image of the original is irradiated and formed by the exposure device 3, and the electrostatic latent image is carried on the outer peripheral surface of the photosensitive drum 1. Thereafter, the electrostatic latent image is developed while passing through a portion of the developing device 4. The developed toner image is transferred onto the transfer paper P by a transfer device including the transfer roller 5. After the transfer sheet P is separated from the photosensitive drum 1, residual toner is removed by the cleaning device 6. Thereafter, the residual potential on the surface of the photosensitive drum 1 is removed by a neutralizing lamp (not shown) to prepare for the next copy. The transfer paper P onto which the toner image has been transferred passes through a fixing device (not shown) and is discharged outside the apparatus. As the transfer device, for example, a method using an electrostatic roller, a method using corona discharge, an adhesive transfer method, a thermal transfer method, or the like can be used. As the fixing device, for example, a thermal transfer method, solvent fixing, UV fixing, pressure fixing, or the like can be used.
[0016]
The developer 7 used in the copying machine of the present embodiment is a low-viscosity (about 1 cSt) and low-density (about 1%) liquid development using Isopar (exxon trademark) as a carrier that is generally commercially available. It is not a developer but a liquid developer with high viscosity and high concentration. As the viscosity and concentration range of the developer, for example, those having a viscosity of 50 cSt to 5000 cSt and a concentration of 5% to 40% are used. As the carrier liquid, a highly insulating material such as silicone oil, normal paraffin, Isopar M (Exxon trademark), vegetable oil, mineral oil or the like is used. Volatile and non-volatile can be selected according to the purpose. The particle size of the toner can be selected from submicron to about 6 μm according to the purpose.
[0017]
Next, the developing device 4 will be described. As shown in the figure, the developing device 4 mainly comprises a developer containing tank 8 for containing developer, a developing roller 9, a sweep roller 11, an anilox roller 12 as a coating means, a gear pump (not shown), and a stirring roller 13. Has been. The developing roller 9 and the sweep roller 11 are provided with cleaning members 14a and 14b made of metal blades or rubber blades, respectively. The cleaning member is not limited to a blade but may be a roller type. The anilox roller 12 is provided with a doctor blade 15.
[0018]
The developing roller and the sweep roller 11 are provided with elastic layers 9a and 11a having conductivity on the outer peripheral surface, respectively. Urethane rubber can be used as the material of these elastic layers 9a and 11a. The rubber hardness of each elastic layer 9a, 11a is preferably 50 degrees or less in terms of JIS-A hardness. The material of the elastic layers 9a and 11a is not limited to urethane rubber, but may be any material that has conductivity and does not swell or dissolve in the carrier liquid / developer. The surfaces of the developing roller 9 and the sweep roller 11 are electrically conductive and do not swell or dissolve with the carrier liquid / developer, and the carrier liquid / developer 7 is not in contact with the inner layer. If there is, the material of each elastic body layer 9a, 11a as the inner layer may have elasticity without restriction of the conductivity and swelling and dissolution. At this time, the developing bias voltage and the sweep bias voltage need to be applied from the surface, not from the shafts of the developing roller 9 and the sweep roller 11.
Instead of a configuration in which the elastic layer is provided on the developing roller 9 and the sweep roller 11, a configuration in which the elastic layer is provided on the photosensitive member side may be employed. Further, the photoreceptor may be constituted by an endless belt-like member. Further, the developing roller 9 and the sweep roller 11 are configured such that the surfaces thereof have smoothness of Rz 3 μm or less by coating or a tube.
[0019]
When the developing roller and the sweep roller 11 are brought into contact with the photosensitive drum 1 with an appropriate pressure, the elastic layers 9a and 11a of the rollers are elastically deformed to form the developing nip 17 and the removal nip 16. . In particular, by forming the developing nip 17, it is possible to secure a certain developing time for the toner of the developer 7 to move and adhere to the photosensitive drum 1 by the developing electric field in the developing region. By adjusting the contact pressure, it is possible to adjust the nip width, which is the size of each nip portion in the surface movement direction. Each nip width is set to be equal to or greater than the product of the linear speed of each roller and the development time constant. Here, the development time constant is a time required until the development amount is saturated, and is obtained by dividing the nip width by the process speed. For example, if the nip width is 3 mm and the process speed is 300 mm / sec, the development time constant is 10 msec.
[0020]
During the developing operation, a thin layer of developer is formed on the developing roller by the anilox roller 12. At this time, the thickness of the developer 7 applied on the developing roller 9 is 1 cm on the surface. ² The pigment content in the toner carried per hit was set to be 3 μg or more and 60 μg or less. For this purpose, a thin layer of developer 7 was applied to a thickness of 3 to 10 μm. This is because the coating thickness of the developer 7 is 1 cm on the surface of the developing roller 9. ² When the thickness is such that the pigment content in the toner carried per hit is less than 3 μg, a sufficient amount of pigment does not move to the image portion of the latent image formed on the photosensitive drum 1, and the image portion This is because the image density may be reduced. Also, 1 cm of the surface of the developing roller 9 ² This is because if the thickness of the toner contained in the toner held per unit is greater than 60 μg, the excess toner remaining on the background after development increases and the removal by the sweep roller may be incomplete. .
[0021]
The thin layer of the developer 7 formed on the surface of the developing roller passes through the developing nip 17 formed by the photosensitive drum 1 and the developing roller 9. In general, in an electrophotographic developing device, the surface moving speed of the developing roller is set faster than the surface moving speed of the photosensitive member in order to send sufficient toner to a region where the photosensitive member and the developing device face each other. For this reason, since the toner has a high moving speed with respect to the surface of the photosensitive member, a positional deviation occurs between the toner and the latent image, and the leading edge of the image is blurred or the balance between the vertical and horizontal lines is poor. Appear. This phenomenon is also observed in liquid development. In the copying machine according to the present embodiment, the surface of the developing roller 9 and the surface of the photosensitive drum 1 move at a substantially constant speed, and has a velocity vector in the tangential direction of the photosensitive drum 1 relative to the toner. Therefore, the above phenomenon does not occur.
[0022]
A developing bias voltage (400 V) lower than the photoreceptor surface potential (600 V) is applied to the developing roller, and a developing electric field is generated between the developing roller and an image portion exposed to 50 V or less. In the image portion of the photosensitive drum 1, the toner in the developer 7 is moved to the photosensitive drum 1 by the electric field to visualize the latent image. On the other hand, in the background portion (non-image portion), the toner is moved to the surface of the developing roller 9 by the electric field formed by the developing bias potential and the photoreceptor potential so that the toner does not adhere to the background portion.
[0023]
However, if a part of the toner on the background portion does not move to the surface of the developing roller 9 and remains on the photosensitive drum 1 side, it causes fogging. Therefore, the above-described sweep roller is provided to sweep (clean) toner that causes the fog (hereinafter referred to as “fogging toner”). The sweep roller is disposed downstream of the developing roller 9 in the rotation direction of the photosensitive drum 1 and is pressed against the photosensitive drum 1 so as to sandwich the developed toner layer. The surface of the sweep roller 11 moves at substantially the same speed as the surface of the photosensitive drum 1.
[0024]
The sweep roller 11 has a bias voltage (250 V) close to the surface potential (50 to 200 V) of the toner layer of the image portion on the photosensitive drum 1 so that the toner does not return to the sweep roller 11 from the toner layer of the developed image portion. ) Is applied. In the background portion, the floating fog toner is moved to the sweep roller 11 by an electric field generated by the difference between the potential of the background portion of the photosensitive drum 1 and the potential due to the bias voltage. At this stage, the background developer layer is about half the thickness of the developing nip portion of the developing roller 9, and the toner density is reduced to about 50% or less of the density before development. Removal is easy. Thereby, fogging of the background portion can be completely prevented. The above-described potential relationship can be expressed by the following equation.
Background portion potential>VB1>VB2> Image portion toner layer potential
Here, VB1 is a potential between the surface of the photosensitive drum 1 tube and the developing roller 9, and VB2 is a potential between the surface of the photosensitive drum 1 tube and the sweep roller 11.
[0025]
By installing the sweep roller, about 70% of excess carrier liquid adhering to the background portion on the photosensitive drum 1 during development can be removed.
[0026]
Further, since the fog toner can be efficiently removed by the sweep roller 11, a little fog toner may remain in the developing nip 17 between the photosensitive drum 1 and the developing roller 9, and the fog removing electric field (developing roller 9 The potential difference between the developing bias applied to the photosensitive member and the photosensitive member charging potential) can be kept low. Therefore, the charged potential of the photosensitive drum 1 can be lowered. As a result, various advantages such as an improvement in the durability of the photosensitive drum 1, a reduction in the burden on the charging device 2, and a reduction in exposure power occur.
[0027]
In the above-described example, the case where an image is formed by reversal development has been described as one embodiment, but an image can also be formed by regular development. In the case of regular development, the relationship between each potential is set as in the following equation in the copying machine having the above configuration.
Photoconductor potential> Image portion toner layer potential>VB2>VB1> Non-image portion potential
Here, VB1 is a potential between the surface of the photosensitive drum 1 tube and the developing roller 9, and VB2 is a potential between the surface of the photosensitive drum 1 tube and the sweep roller 11.
[0028]
As an example of a specific potential, in the case of negatively charged toner, the photosensitive member potential is set to + 600V, the image portion toner layer potential is set to + 500V, VB2 is set to + 300V, VB1 is set to + 100V, and the non-image portion potential is set to + 50V.
[0029]
Next, an example of a method for producing a developer carrying member used in the developing device of the image forming apparatus according to the present invention, in this case, a developing roller 9 having an endless belt-like member and a non-elastic developing roller 9 is provided. The case of using will be described with reference to FIG.
[0030]
First, a developing roller as a developer carrier having at least the surface thereof constituted by the nickel layer 93 is manufactured. The surface nickel layer 93 is positively oxidized by at least one of the following five processes to form an oxide film 94 on the surface, which is used as a developing roller base material. The first means is to expose the nickel layer 93 together in a temperature environment necessary for surface oxidation for a predetermined time. In the case of the nickel layer 93, it is desirable to expose in an environment of 270 ° C. or higher for 30 minutes or longer. The second means is to expose the nickel layer 93 under ultraviolet light having a wavelength of 400 nm or less for a predetermined time. The light source may be a normal halogen lamp, but in order to increase the decomposition efficiency of oxygen molecules, it is desirable to use a short wavelength light source such as an excimer lamp and expose for 5 minutes or more. Excimer laser irradiation is also effective from the viewpoint of energy efficiency. The third means exposes the nickel layer 93 under an infrared lamp or flash, and the fourth means exposes the oxygen layer under oxygen plasma ionized or radicalized by electromagnetic waves or high frequency voltage. The fifth means is exposure under an oxygen beam.
[0031]
The base material of the developing roller surface-oxidized by any of the above means is coated with a fluorine-based material 95 as an amorphous resin having a critical surface tension of 25 mN / m or less and having at least one hydrolyzable functional group. In this way, the developing roller 9 in which the outermost surface of the developing roller is coated with the fluorine material 95 is formed. The developing roller 9 manufactured in this way is mounted on the developing unit, and the developing device 4 is manufactured.
[0032]
As the fluorine-based material 95, developing rollers were manufactured for a total of six cases where the following five kinds of materials were coated and when the above-mentioned positive surface oxidation was not applied to the base portion 92 of the developing roller 9. Each will be described below.
[0033]
Example 1
Using a suitable perfluorocarbon as a solvent, an alcohol-terminated perfluoropolyether 20% by weight solution was prepared, and the substrate of the developing roller was immersed in the solution for 5 minutes or more. Thereafter, the hydrolysis reaction was completed by leaving it in an environment of at least 50 ° C. and 250 ° C. for 15 minutes or longer. Desirable conditions are 80 to 200 ° C. and 30 minutes or more. There is concern about the decomposition of the fluorine material itself under the condition of 200 ° C. or higher. The manufactured coating thickness was 10 nm or less.
[0034]
Example 2
An alkoxysilane terminal-modified perfluoropolyether 20% by weight solution was prepared using a suitable perfluorocarbon as a solvent, and the substrate of the developing roller was immersed in the solution for 5 minutes or more. Thereafter, the hydrolysis reaction was completed by leaving it in an environment of at least 50 ° C. and 250 ° C. for 15 minutes or longer. Desirable conditions are 80 to 200 ° C. and 30 minutes or more. There is concern about the decomposition of the fluorine material itself under the condition of 200 ° C. or higher. The manufactured coating thickness was 10 nm or less.
[0035]
Example 3
Using a suitable perfluorocarbon as a solvent, a carboxylic acid terminal-modified perfluoropolyether 20% by weight solution was prepared, and the substrate of the developing roller was immersed in the solution for 5 minutes or more. Thereafter, the hydrolysis reaction was completed by leaving it in an environment of at least 50 ° C. and 250 ° C. for 15 minutes or longer. Desirable conditions are 80 to 200 ° C. and 30 minutes or more. There is concern about the decomposition of the fluorine material itself under the condition of 200 ° C. or higher. The manufactured coating thickness was 10 nm or less.
[0036]
Comparative Example 1
A 0.1% by weight solution of fluoroalkylsilane (Toshiba Silicone TSL8355) was prepared using a suitable perfluorocarbon as a solvent, and the substrate of the developing roller was immersed in the solution for 5 minutes or more. Thereafter, the hydrolysis reaction was completed by leaving it in an environment of at least room temperature for 15 minutes or longer. Desirable conditions are 80 to 200 ° C. for 1 hour. There is concern about the decomposition of the fluorine material itself under the condition of 200 ° C. or higher. The manufactured coating thickness was 10 nm or less.
[0037]
Comparative Example 2
A 0.1% by weight solution of an amorphous fluororesin (Teflon AF manufactured by DuPont) having a glass transition point of 100 ° C. or higher was prepared using a suitable perfluorocarbon as a solvent, and the substrate of the developing roller was immersed in the solution for 5 minutes or longer. . Thereafter, the hydrolysis reaction was completed by leaving it in an environment of at least 50 ° C. and 250 ° C. for 15 minutes or longer. Desirable conditions are 80 to 200 ° C. and 30 minutes or more. There is concern about the decomposition of the fluorine material itself under the condition of 200 ° C. or higher. The manufactured coating thickness was 10 nm or less.
[0038]
Comparative Example 3
The material described in Example 1 was coated in the same process as in Example 1 on the base portion 92 of the developing roller that was not subjected to aggressive surface oxidation.
[0039]
The above six types of developing roller 9 were incorporated into a developing unit, image formation was repeated, and the filming state of toner on the roller surface was observed. The result is shown in FIG. In FIG. 3, the horizontal axis represents the number of printed A4 horizontal transfer sheets, and the vertical axis represents the developing roller filming state. In this graph, the material within the tolerance level region is a material that sufficiently satisfies the specifications.
[0040]
As is clear from FIG. 3, Examples 1 and 2 were effective, and Comparative Examples 1 to 3 could not satisfy the specifications. In Examples 1 to 3, the filming formation rate is slow, and the effect of the main chain of perfluoropolyether having a recovery function against microfracture due to friction appears. Compared with the first and second embodiments, the third embodiment has a poor filming state as a whole. In Examples 1 and 2, the hydrolysis is almost completed and the fluorine-based material is strongly bonded to the base material of the developing roller 9, but in Example 3, the base material of the developing roller is compared with this. The coupling rate to is low.
[0041]
Comparative Example 1 is a type in which an alkoxysilane group similar to Example 2 is bonded to the substrate of the developing roller 9 by hydrolysis, but does not have a recovery function against microfracture due to friction because it is not a perfluoroether main chain. Therefore, the deterioration rate of the contact angle is faster than that of the materials of Examples 1 to 3. In Comparative Example 2, since the coated fluororesin is a material that does not have a chemical bond with the base material of the developing roller and does not have a recovery function, the coating was almost completely peeled off after about 10,000 sheets were printed. Comparative Example 3 was intermediate between Comparative Example 1 and Comparative Example 2. This is because the active surface oxidation treatment is not performed on the base material portion 92 of the developing roller, so that the density of chemical bonding is low. The thickness of the oxide film on the base of the untreated developing roller is less than 1 nm, and it has been confirmed by an ellipsometer that an oxide film of 1 nm or more is formed when the above-described positive surface oxidation treatment is performed.
[0042]
Summarizing the above results, the durability against friction is the logical product of the peeling portion recovery effect as a liquid phase in the practical temperature range caused by the main chain structure and the bonding degree (density) of the functional group that performs chemical bonding. The following tendencies are shown in descending order of durability. Liquid Phase and Development Roller Base Surface Oxidation and Hydrolysis Group (Examples 1 and 2)> Liquid Phase and Development Roller Base Surface Oxidation and Weak Hydrolysis Group (Example 3)> Development Roller Base Material Surface oxidation and hydrolysis group (Comparative Example 1)> Liquid phase and hydrolysis group (Comparative Example 3).
[0043]
In this embodiment, a nickel base material is used as the base material of the developing roller. However, a silicon base material is used to positively oxidize the surface by at least one of the first to fifth steps described above. The same tendency was obtained when the developing roller 9 was formed by using a dry process on a silicon substrate that had been processed to form an oxide film of 1 nm or more on the surface and a silicon substrate that was not actively oxidized.
[0044]
A polymer such as polyimide or polysulfone is used as a base material for the developing roller, and at least one of the first to fifth aggressive oxidation treatment steps described above is performed on the surface of the polymer so that the contact angle with water is 25. The same tendency was also obtained when the developing roller 9 was made of a polymer having a surface that was set to be less than 0 ° C. and an untreated polymer.
[0045]
A non-oxide ceramic such as silicon carbide or silicon nitride is subjected to at least one of the first to fifth aggressive oxidation processes described above to form an oxide film of 1 nm or more on the surface. The same tendency was obtained when the developing roller 9 was made of non-oxide ceramics without active oxidation treatment.
[0046]
Even when an oxide ceramic such as zirconia or alumina was used as the developing roller 9, the effect of the liquid phase and the effect of the hydrolysis group were the same.
[0047]
In this example, the coating thickness of the fluorine-based material 95 was set to 10 nm. However, as a result of an experiment in which the thickness was changed, it became clear that there was an effect when the thickness was 1 nm or more. Below this, even if the initial characteristics were good, the recovery function as an effect as a liquid phase resin was not obtained, and the contact angle deterioration characteristics similar to those of Comparative Example 1 were exhibited.
[0048]
In the above example, the developing roller 9 having no elastic layer is shown. However, when an elastic material is used, the developing roller 9 may be formed as an elastic layer. The fluorine material layer may be applied to the surface layer of the sweep roller to which an electric field similar to that of the developing roller 9 is applied.
[0049]
【The invention's effect】
According to the first aspect of the present invention, there is obtained a developer carrying member in which the coating material is bonded to the base of the developing roller and the toner hardly forms a film.
[0050]
According to the second aspect of the present invention, against the slight peeling of the amorphous resin which is unavoidable due to friction when the cleaning blade, the toner application member and other members are always brought into contact with the surface of the developer carrying member and rotated. As a result, the peeled portion can be covered quickly, and the toner can be prevented from filming.
[0051]
According to the third to fifth aspects of the present invention, the main chain portion of the amorphous resin is partly strongly adhered to the developer carrier base material to obtain durability against various frictions with respect to the developer carrier. Can do.
[0052]
According to the invention of claim 6, the main chain portion of the amorphous resin is partially and more closely adhered to the developer carrier substrate, and durability against various frictions with respect to the developer carrier can be obtained. .
[0053]
According to the seventh aspect of the present invention, when partially peeled, a recovery function which is an effect as a liquid phase resin can be obtained, and durability against various frictions against the developer carrying member can be obtained.
[0054]
According to the invention of claim 8, it becomes possible to strongly bond the amorphous resin having a hydrolyzable functional group to the base material of the developer carrying member without performing a special oxidation treatment. The durability against various frictions with respect to the carrier can be obtained, and a developer carrier having a small number of strokes and a high yield can be provided.
[0055]
According to the ninth aspect of the present invention, the amorphous resin can be strongly bonded to the base material of the developer carrying member, and durability against various frictions with respect to the developer carrying member can be obtained.
[0056]
According to the invention of claim 10, it is possible to strongly bond the amorphous resin to the developer carrier base material, it is possible to obtain durability against various frictions with respect to the developer carrier, and drive at high speed. It can be used for development stably and continuously in the developer carrier.
[0057]
According to the invention of claim 11, it becomes possible to strongly bond the amorphous resin having a hydrolyzable functional group to the base material of the developer carrier, and durability against various frictions with respect to the developer carrier. And a developer carrier having a high yield can be provided.
[0058]
According to the twelfth aspect of the present invention, it is possible to provide a developer bearing member in which toner is not filmed stably and stably.
[0059]
According to the thirteenth aspect of the present invention, it is possible to oxidize a large amount of material, and the process yield is improved.
[0060]
According to the fourteenth aspect of the present invention, it is possible to suppress the thermal dimensional change of the developer carrier material, and the process yield is improved.
[0061]
According to the fifteenth aspect of the present invention, processing can be performed in a short time, and the process yield is improved.
[0062]
According to the invention of the sixteenth aspect, it is possible to suppress thermal dimensional change of the developer carrier material and to perform precise process management of the oxidation treatment, thereby improving the process yield.
[Brief description of the drawings]
FIG. 1 is a front view showing a schematic configuration of a color copying machine according to an embodiment of the present invention.
FIG. 2 is a schematic enlarged view of a developing roller surface layer.
FIG. 3 is a diagram showing the relationship between the number of prints and the state of developing roller filming.
[Explanation of symbols]
1 Photosensitive drum
4 Development device
7 Developer
9 Developing roller
11 Sweep Roller
12 Anilox Roller
13 Stirrer roller
14a, 14b Cleaning member
15 Doctor blade
16 nip
17 Nip
92 Base material part
93 Nickel layer
94 Oxide film
95 Fluorine material
P transfer paper

Claims (16)

In an image forming apparatus for developing a latent image formed on a latent image carrier with a liquid developer carried on the liquid developer carrier,
At least when the developer carrying member is an inorganic oxide or other than an inorganic oxide, it is composed of an inorganic or organic material that has been subjected to a positive surface oxidation treatment other than being left at room temperature, and has a critical surface tension of 25 mN / m. In the following, the amorphous resin having at least one hydrolyzable functional group has bonded the material via oxygen at least on the surface of the developer carrying member, and the resin has a temperature of 0 ° C. to 70 ° C. An image forming apparatus characterized by satisfying a condition of being in a liquid phase within a temperature range of ° C.   2. The image forming apparatus according to claim 1, wherein perfluoropolyether is used in the main chain as an amorphous resin in the developer carrying member.   2. The image forming apparatus according to claim 1, wherein the developer carrying member has an alcohol group or an alkoxy group, preferably a methoxy group or an ethoxy group as a hydrolyzable functional group.   2. The image forming apparatus according to claim 1, wherein the developer carrying member has a silanol group or an alkoxysilane group, preferably a methoxysilane group or an ethoxysilane group as a hydrolyzable functional group. .   2. The image forming apparatus according to claim 1, wherein the developer carrying member has a carboxyl group or an ester group, preferably a methyl carbonate group or an ethyl carbonate group as a hydrolyzable functional group. apparatus.   A developer carrier having a methylene group in which at least one hydrogen is replaced with bromine or iodine is present between the functional group according to claim 3 or 4 and the main chain according to claim 2. Image forming apparatus.   2. The image forming apparatus according to claim 1, wherein the coating thickness of the amorphous resin on the developer carrying member is 1 nm or more.   2. The image forming apparatus according to claim 1, wherein an oxide ceramic material mainly composed of zirconia or alumina is used on at least the surface of the developer carrier as a material of the developer carrying member.   2. The image forming apparatus according to claim 1, wherein a non-oxide ceramic material such as silicon carbide or silicon nitride is used at least on the surface of the developer carrying member, and an oxide film having a thickness of 1 nm or more is formed on the surface. An image forming apparatus comprising:   2. The image forming apparatus according to claim 1, wherein a material having a main composition of silicon or nickel is used at least on a surface of the developer carrier, and an oxide film having a thickness of 1 nm or more is formed on the surface. An image forming apparatus.   2. The image forming apparatus according to claim 1, wherein at least the surface of the developer carrying member is made of a material mainly composed of an organic material typified by polyimide or polysulfone, and is subjected to surface oxidation treatment for water. An image forming apparatus having a contact angle of 25 ° or less.   A liquid developing device comprising the developer carrying member according to claim 1. A method for oxidizing a surface of a developer carrying member used in the image forming apparatus according to any one of claims 9 to 11 ,
A method for oxidizing the surface of a developer carrier, wherein at least the surface material of the developer carrier is exposed to a temperature environment necessary for surface oxidation . A method for oxidizing a surface of a developer carrying member used in the image forming apparatus according to any one of claims 9 to 11 ,
A method for oxidizing a surface of a developer carrying member, wherein at least a surface material of the developer carrying member is exposed to ultraviolet rays having a wavelength of 400 nm or less . A method for oxidizing a surface of a developer carrying member used in the image forming apparatus according to any one of claims 9 to 11 ,
A method for oxidizing a surface of a developer carrying member, comprising exposing at least a surface material of the developer carrying member to infrared flash light . A method for oxidizing a surface of a developer carrying member used in the image forming apparatus according to any one of claims 9 to 11 ,
A method for oxidizing the surface of a developer carrying member, wherein a space in which oxygen is converted into ions or radicals using high-frequency voltage or electromagnetic waves is created, and at least the surface material of the developer carrying member is exposed to the space .

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