JP2016031375A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus having an intermediate transfer body that has flexibility and excellent toner releasing property, suppresses occurrence of irregular density or white voids in an image, and shows excellent transfer property to a sheet having a rough surface property.SOLUTION: The image forming apparatus includes: an image carrier on which a latent image can be formed and a toner image can be carried; developing means that develops the latent image with a toner; an intermediate transfer body to which the toner image is primarily transferred; transfer means that secondarily transfers the toner image on the intermediate transfer body onto a recording medium; and lubricant supply means that supplies a lubricant to an upper surface of the intermediate transfer body. The intermediate transfer body has a layered structure comprising at least a base layer and a surface layer. The surface layer contains a crosslinked body of polyrotaxane having at least cyclic molecules, linear molecules including the cyclic molecules in a skewered state, and blocking groups disposed at both terminals of the linear molecule to prevent the cyclic molecules from detaching. The lubricant comprises a mixture of zinc stearate and zinc palmitate, or calcium stearate, and the lubricant adheres to the surface of the surface layer of the intermediate transfer body.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image forming apparatus using an intermediate transfer member equipped in an image forming apparatus such as a copy printer, and more particularly to an image forming apparatus using an intermediate transfer member suitable for full-color image formation.

  Conventionally, in an electrophotographic image forming apparatus, a belt, particularly a seamless belt, is used as a member for various purposes. Particularly in recent full-color image forming apparatuses, an intermediate transfer belt system in which developed images of four colors of yellow, magenta, cyan, and black are once color-superposed on an intermediate transfer medium and then collectively transferred to a transfer medium such as paper. Is used.

  Such an intermediate transfer belt method has been used in a system that uses a four-color developing machine for one photoconductor, but has a drawback in that the printing speed is slow. For this reason, as a high-speed print, a four-tandem tandem method is used in which the photoreceptors are arranged for four colors and each color is continuously transferred to paper. However, in this method, there are fluctuations due to the environment of the paper, etc., and it is very difficult to match the position accuracy of overlapping each color image, causing a color misregistration image. Therefore, in recent years, it has become the mainstream to adopt the intermediate transfer method for the quadruple tandem method.

  Under such circumstances, the required characteristics (high-speed transfer, positional accuracy) of the intermediate transfer belt are also stricter than before, and it is necessary to satisfy the characteristics corresponding to these requirements. Yes. In particular, for positional accuracy, it is required to suppress fluctuation due to deformation such as elongation of the belt itself due to continuous use. Further, the intermediate transfer belt is laid out over a wide area of the apparatus, and is required to be flame retardant because a high voltage is applied for transfer. In order to meet such requirements, polyimide resins, polyamideimide resins, and the like that are high elastic modulus and high heat resistance resins are mainly used as intermediate transfer belt materials.

  However, since the intermediate transfer belt made of polyimide resin has high strength and high surface hardness, a high pressure is applied to the toner layer when the toner image is transferred, and the toner locally aggregates and a part of the image is formed. A so-called hollow image that is not transferred may occur. In addition, contact followability with a contact member at a transfer portion such as a photoreceptor or paper is inferior, so that a partial contact failure portion (gap) occurs in the transfer portion, and transfer unevenness may occur.

  In recent years, full-color electrophotography has been used to form images on various types of paper. In addition to ordinary smooth paper, recycled paper and embossed paper can be used not only from smooth paper but also from slippery and highly smooth paper such as coated paper. Roughly surfaced materials such as Japanese paper and kraft paper are increasingly used. Such followability to papers having different surface properties is important. If the followability is poor, unevenness of the unevenness of the paper and unevenness of color tone occur.

In order to solve this problem, various intermediate transfer belts in which a relatively flexible elastic layer is laminated on a base layer have been proposed.
However, when the surface layer is a relatively flexible layer, the transfer pressure is reduced and the followability to paper irregularities is improved, but the toner cannot be released well due to the poor surface releasability. There is a problem that transfer efficiency is lowered and the former effect cannot be utilized. There is also a problem that it is inferior in wear resistance and scratch resistance.

  In Patent Document 1, an intermediate transfer member has a two-layer structure in which a surface layer is laminated on a base layer, and an improvement in transferability is proposed by setting the outermost surface hardness higher. However, in the configuration of Patent Document 1, as described above, transferability to a paper having rough surface properties such as recycled paper, embossed paper, Japanese paper, and kraft paper is deteriorated due to poor followability.

  Patent Document 2 proposes an improvement in durability and transferability by using an intermediate transfer member having a three-layer structure of a base layer, an elastic layer, and a surface layer, and forming the surface layer as a thin film hard coating. However, in the configuration of Patent Document 2, since the outermost surface is hard, followability to paper with rough surface properties is inevitably low, and the image quality required recently is not reached and is insufficient.

  Patent Document 3 proposes an improvement in durability by using polyrotaxane in the surface layer of the photoreceptor. However, this proposal relates to a photoreceptor, and the gist of the present invention is different from that of the present invention. The same applies to Patent Documents 4, 5, 6, and 7, which relate to automobile paints.

Patent Document 8 proposes to improve the flaw repairability and transferability by using a surface layer of a material obtained by mixing polyurethane, which is a polymer of acrylic resin and isocyanate, and polyimide. However, in the proposed configuration, the compatibility between the polyurethane and the polyimide is poor, and the unevenness in hardness depending on the location occurs, so that the image quality required recently is not reached. In addition, there is a drawback that the image is likely to be blurred (spotted density unevenness).
In any of the conventional techniques, it is impossible to achieve both improvement in followability to the transfer medium and toner releasability, and transfer unevenness (so-called white spots and blurring) has not been solved. Further, when a flexible layer is introduced, there is a problem that the transfer residual toner cannot be removed by the cleaning blade.

  The present invention has been made in view of the above-described prior art, is flexible and excellent in toner releasability, suppresses the occurrence of uneven image density and white spots, and is highly transferable to paper with rough surface properties. It is an object of the present invention to provide an image forming apparatus having an intermediate transfer member that can achieve both a high rate and a high cleaning performance with a cleaning blade.

As a result of intensive studies, the present inventors have
A latent image is formed and an image carrier capable of carrying a toner image; a developing unit that develops the latent image formed on the image carrier with toner; and a toner image developed by the developing unit is primarily transferred. An intermediate transfer body, a transfer means for secondary transfer of a toner image carried on the intermediate transfer body to a recording medium, and a lubricant supply means for supplying a lubricant to the upper surface of the intermediate transfer body. An image forming apparatus comprising:
The intermediate transfer member has a laminated structure comprising at least a base layer and a surface layer,
The surface layer includes at least a cyclic molecule, a linear molecule that includes the cyclic molecule in a skewered manner, and a blocking group that is disposed at both ends of the linear molecule and prevents the cyclic molecule from being detached. Including a crosslinked polyrotaxane,
The lubricant comprises a mixture of zinc stearate and zinc palmitate, or calcium stearate;
It has been found that the above problem can be solved by using an image forming apparatus characterized in that the lubricant adheres to the surface of the intermediate transfer member.

  According to the present invention, an intermediate transfer body that suppresses the occurrence of image density unevenness and white spots even on a transfer medium with a rough surface property, and achieves both a high transfer rate and a high cleaning property with a cleaning blade. Can be provided.

An example of a suitable layer structure of the intermediate transfer member in the present invention is shown. It is a schematic diagram which shows notionally the basic structure of the polyrotaxane used suitably by this invention. It is a principal part schematic diagram of an example of the image forming apparatus of this invention. It is a principal part schematic diagram of the other example of the image forming apparatus of this invention.

  In an electrophotographic image forming apparatus, a seamless belt is used for several members. An intermediate transfer member (intermediate transfer belt) is an important member that requires electrical characteristics. The intermediate transfer member in the present invention will be described below.

The intermediate transfer member in the present invention has an image bearing member on which a latent image is formed and can carry a toner image, a developing unit that develops the latent image formed on the image bearing member with toner, and a developing unit that develops the latent image. An intermediate transfer member on which the toner image formed is primarily transferred, transfer means for secondary transfer of the toner image carried on the intermediate transfer member to a recording medium, and lubrication for supplying a lubricant to the surface of the intermediate transfer member An intermediate transfer member used in an image forming apparatus having an agent supply means, and an intermediate transfer belt type image forming apparatus [a plurality of images formed sequentially on a so-called image carrier (for example, a photosensitive drum)] Suitable for use as an intermediate transfer belt in an apparatus in which a color toner developed image is sequentially superimposed on an intermediate transfer belt to perform primary transfer, and the primary transfer image is collectively transferred to a recording medium. It is.
FIG. 1 shows a layer structure of an intermediate transfer belt preferably used in the present invention. As a configuration, a flexible surface layer 12 is laminated on a rigid base layer 11 that can be relatively flexible. A lubricant 13 is attached to the surface of the surface layer. The lubricant is a lubricant containing zinc stearate and zinc palmitate, or a lubricant containing calcium stearate.

<Base layer>
First, the base layer 11 will be described. Examples of the constituent material include a material containing a filler (or additive) for adjusting electric resistance in the resin, that is, a so-called electric resistance adjusting material.
As such a resin, from the viewpoint of flame retardancy, for example, a fluorine-based resin such as PVDF, ETFE, a polyimide resin, or a polyamide-imide resin is preferable. From the viewpoint of mechanical strength (high elasticity) and heat resistance, A polyimide resin or a polyamideimide resin is preferred.

Examples of the electrical resistance adjusting material include a metal oxide, carbon black, an ionic conductive agent, and a conductive polymer material. Examples of the metal oxide include zinc oxide, tin oxide, titanium oxide, zirconium oxide, aluminum oxide, and silicon oxide. Moreover, in order to improve dispersibility, the metal oxide may be subjected to surface treatment in advance. Examples of carbon black include ketjen black, furnace black, acetylene black, thermal black, and gas black. Examples of the ionic conductive agent include tetraalkylammonium salts, trialkylbenzylammonium salts, alkylsulfonates, alkylbenzenesulfonates, alkyl sulfates, glycerol fatty acid esters, sorbitan fatty acid esters, polyoxyethylene alkylamines, polyoxyethylene fatty acids. Alcohol ester, alkyl betaine, lithium perchlorate, etc. are mentioned, and these may be used in combination.
The electrical resistance adjusting material in the present invention is not limited to the above exemplary compounds.
In addition, the coating liquid containing at least the resin component in the method for producing a seamless belt of the present invention further contains additives such as a dispersion aid, a reinforcing material, a lubricant, a heat conductive material, and an antioxidant as necessary. May be.

The case of using a seamless belt is preferably equipped as an intermediate transfer belt, as a resistance value, preferably ^{1 × 10 8 ~1 × 10 13} Ω / □ in surface resistivity, 1 × 10 ⁸ to 1 volume resistivity The amount of carbon black to be × 10 ¹¹ Ω · cm is contained, but from the viewpoint of mechanical strength, a carbon black that can be achieved with an addition amount that is not brittle and does not easily break is selected. In other words, in the case of an intermediate transfer belt, an electrical characteristic (for example, a coating liquid in which the blending of the resin component (for example, a polyimide resin precursor or a polyamideimide resin precursor) and an electrical resistance adjusting material is appropriately adjusted is used. It is preferable to manufacture and use a seamless belt having a balance between surface resistivity and volume resistivity) and mechanical strength.

  There is no restriction | limiting in particular as thickness of the said base layer, Although it can select suitably according to the objective, 30 micrometers-150 micrometers are preferable, 40 micrometers-120 micrometers are more preferable, 50 micrometers-80 micrometers are especially preferable. When the thickness of the base material layer is 30 μm or more, the belt does not tear due to cracks, and when the thickness is 150 μm or less, the belt does not crack due to bending. On the other hand, when the thickness of the base layer is within the particularly preferable range, it is advantageous in terms of durability.

  The method for measuring the thickness of the base layer is not particularly limited and can be appropriately selected according to the purpose. For example, measurement with a contact type or eddy current type thickness meter or a cross section of the film can be performed by scanning electron The method of measuring with a microscope (SEM) is mentioned.

  In the case of carbon black, the content of the electric resistance adjusting material in the present invention is 10 to 25% by mass, preferably 15 to 20% by mass, based on the total solid content in the coating liquid. Moreover, as content in the case of a metal oxide, it is 1-50 mass% of the total solid of a coating liquid, Preferably it is 10-30 mass%. When the content is less than the range of each of the electric resistance adjusting materials, it becomes difficult to obtain uniformity of the resistance value, and the fluctuation of the resistance value with respect to an arbitrary potential increases. On the other hand, when the content is larger than the above ranges, the mechanical strength of the intermediate transfer belt is lowered, which is not preferable in practical use.

  As polyimide and polyamideimide in the present invention, general-purpose products from manufacturers such as Toray DuPont, Ube Industries, Shin Nippon Rika, JSR, Unitika, IST, Hitachi Chemical, Toyobo, Arakawa Chemical, etc. are obtained and used. can do.

<Surface>
Next, the surface layer 12 laminated on the base layer 11 will be described. The surface layer is a crosslinked polyrotaxane having at least a cyclic molecule, a linear molecule that includes the cyclic molecule in a skewered manner, and a blocking group that is disposed at both ends of the linear molecule to prevent the elimination of the cyclic molecule. And a lubricant is adhered to the surface of the surface layer.
In order to keep the flexibility of the polyrotaxane moderately, the surface layer can be crosslinked with a curing agent so that the surface layer can have a preferable hardness for transferability, and the lubricant is attached to the surface of the surface layer to release the toner. And the transfer rate can be improved. Furthermore, since the lubricant adheres to the surface of the surface layer, the friction coefficient between the surface layer and the cleaning blade is reduced, and high cleaning performance can be realized.

<Polyrotaxane>
FIG. 2 is a schematic diagram conceptually showing the basic structure of the polyrotaxane used in the present invention. Here, polyrotaxane refers to a molecule in which a cyclic molecule is inserted into a dumbbell-shaped linear upper axis molecule. By using a polymer such as polyethylene glycol as the axis molecule, a cyclic molecule such as cyclodextrin is formed. The one confined in plural is called polyrotaxane. Dumbbell-shaped portions at both ends play a role of preventing the elimination of the cyclic molecule, that is, a blocking group. In addition, the dumbbell-shaped linear molecule having blocking groups at both ends is not covalently bonded to the cyclic molecule.
Therefore, the linear molecule can freely move in the hole of the cyclic molecule, and the cyclic molecule can also move along the linear molecule.
Further, either one or both of a linear molecule and a cyclic molecule constituting the polyrotaxane may have a lipophilic modification group. As a result, it becomes easy to dissolve in an organic solvent and to be easily applied as a surface layer.
In the present invention, the lipophilic modified polyrotaxane refers to a polyrotaxane in which either one or both of a linear molecule and a cyclic molecule have a lipophilic modification group. Examples of the modifying group exhibiting lipophilicity include an alkyl group and a benzyl group.

  In FIG. 2, this lipophilic modified polyrotaxane 1 has a linear molecule 2, a cyclodextrin that is a cyclic molecule 3, and a blocking group 4 disposed at both ends of the linear molecule. Here, the blocking group 4 needs to be sufficiently bulky so that the cyclodextrin molecule cannot be detached from the chain polymer molecule having the terminal functional group. The linear molecule 2 penetrates the hole (opening) of the cyclic molecule 3 and is included by the cyclic molecule 3, and the cyclic molecule 3 has a lipophilic modification group 3A. That is, when stress is applied, the cyclic molecule 3 can move freely along the linear molecule 2 like a pulley. As a result, the stretchability and flexibility are excellent, and the followability to the transfer medium is improved.

  Here, the linear molecule may be substantially linear, and any molecule having a reactive functional group capable of binding a blocking group at its end can be used without any limitation. . For example, the linear molecule includes polyethylene glycol, and the blocking group includes an adamantane group.

The chain polymer molecule having a terminal functional group preferably has a molecular weight of 1,000 to 50,000, more preferably 10,000 to 40,000, and even more preferably in the range of 20,000 to 35,000. It is particularly preferred that
When the molecular weight of the linear molecule is 1,000 or more, the pulley effect by the cyclic molecule is sufficiently obtained, the flexibility of the coating film is not lowered, and the scratch resistance and the followability to the transfer medium are deteriorated. There is nothing to do. When the molecular weight is 50,000 or less, the viscosity of the coating liquid does not become too high, and appearance deterioration such as smoothness and gloss does not occur.

  The cyclic molecule in the polyrotaxane can be used without any limitation as long as it can move through the chain molecule in the ring. Further, the cyclic molecule is not necessarily completely closed, and a part of the ring may be opened to the extent that it does not leave the chain molecule.

  Furthermore, as the cyclic molecule, those having a reactive group are preferable in that the binding with the above-described lipophilic modification group is facilitated. Examples of such a reactive group include a hydroxyl group, a carboxyl group, an amino group, and the like, but the reactive group does not react with the blocking group when forming the blocking group. Those having the following are preferred.

  As the cyclic molecule, any cyclic molecule can be used without any limitation as long as the cyclic molecules are not cross-linked and can pass a chain polymer molecule into the ring. Suitable cyclic molecules include cyclodextrins and crown ethers. Among these, cyclodextrins are particularly preferable because they can easily form an inclusion compound with an organic compound.

Cyclodextrins are compounds in which a plurality of glucoses are linked in a cyclic manner with α-1,4-bonds. Among them, compounds formed with 6, 7, and 8 glucoses are α-, β-, And γ-cyclodextrin and more preferably used. From the viewpoint of inclusion, α-cyclodextrin is preferably used.
In addition, modified dextrins in which at least one of the hydroxyl groups of these cyclodextrins is substituted with another organic functional group are more preferably used in terms of improving the solubility in a solvent.

The above-mentioned cyclic molecules such as cyclodextrin can be used alone or in combination of two or more. In addition, the number (inclusion amount) of the cyclic molecule included in the linear molecule may be arbitrarily set as long as the cyclic molecule itself is within a range in which the linear molecule can move freely like a pulley. Absent.
A polyrotaxane suitable for the present invention includes a cyclic molecule, a linear molecule that includes the cyclic molecule in a skewered manner, and a blocking group that is disposed at both ends of the linear molecule and prevents the cyclic molecule from detaching. Wherein the blocking group is an adamantane group, the cyclic molecule is α-cyclodextrin, part or all of the hydroxyl group of the cyclodextrin is modified with a modifying group, and the modifying group is —C ₃ H ₆ — It has a structure having a (—CO (CH ₂ ) ₅ OH) group, which is a modified group by caprolactone, bonded to an O— group.

  The polyrotaxane in the present invention described above can be produced by a known method, for example, the method of Japanese Patent No. 4376849, or a general-purpose product from a manufacturer such as Advanced Soft Materials can be obtained and used. it can.

  The surface layer of the intermediate transfer member of the present invention contains a crosslinked polyrotaxane. The cross-linked polyrotaxane means a product obtained by cross-linking the above-mentioned polyrotaxane alone with another polymer. That is, in the surface layer of the intermediate transfer member of the present invention, the curing agent that forms the surface layer is bonded to the polyrotaxane through the cyclic portion of the polyrotaxane that also forms the surface layer. With this crosslinked polyrotaxane, excellent transferability can be achieved.

<Curing agent>
Next, the curing agent (crosslinking agent) will be described. Curing agents used in the present invention may be those that are currently on the market and are not particularly limited, but are preferably suitably used so that the surface layer has a preferable hardness for transferability while maintaining the flexibility of the polyrotaxane appropriately. Choose one.
The surface layer of the present invention can be obtained by dissolving the polyrotaxane in an organic solvent, adding a curing agent, coating, drying and copolymerizing.

  Specific examples of the crosslinking agent (curing agent) include melamine resin, polyisocyanate compound, block isocyanate compound, cyanuric chloride, trimesoyl chloride, terephthaloyl chloride, epichlorohydrin, dibromobenzene, glutaraldehyde, phenylene diisocyanate. And diisocyanate trilein, divinylsulfone, 1,1′-carbonyldiimidazole or alkoxysilanes. In the present invention, these may be used singly or in combination of two or more, but isocyanate is preferred from the viewpoint of easy crosslinking. Among them, hexamethylene diisocyanate-based polyisocyanate is highly reactive because hexamethylene diisocyanate has two primary isocyanate groups, and less uncrosslinked OH groups. More excellent releasability, and because hexamethylene diisocyanate has six methylene groups between isocyanate groups, the flexibility of the intermediate transfer member obtained by cross-linking it is excellent, so that transferability is improved. preferable.

Further, blocked isocyanate is more preferable because of high storage stability at room temperature.
Block isocyanate protects active isocyanate groups with blocking agents such as oximes, diketones, phenols, caprolactams, etc., maintains stability under normal conditions, dissociates the blocking agent by heat treatment, and regenerates active isocyanate groups It causes a curing / crosslinking reaction. The isocyanate suitably used in the present invention is a blocked isocyanate of hexamethylene diisocyanate polyisocyanate.
Moreover, you may use the general-purpose goods currently marketed as an isocyanate type hardening | curing agent. For example, Asahi Kasei Chemicals “Duranate”, Mitsui Chemicals “Takenate”, Nippon Polyurethane Industry “Coronate”, Sumika Bayer Urethane “Desmodur” etc. are available from the market.

  In the present invention, the intermediate transfer member does not necessarily have a two-layer structure of a base layer and a surface layer, and an intermediate layer may be provided as necessary. Examples of the intermediate layer include a primer layer for improving adhesiveness and a relatively soft elastic layer such as elastomer or rubber for improving followability to a transfer medium.

Next, an example of a method for producing the belt having the configuration of the present invention will be described. First, a method for producing the base layer 11 will be described.
A method for producing a base layer using a coating solution containing at least a resin component, that is, a coating solution containing a polyimide resin precursor or a polyamideimide resin precursor will be described. The base layer can be produced by applying the coating solution by a known method such as spiral coating, die coating, or roll coating.
While slowly rotating a cylindrical mold, for example, a cylindrical metal mold, a coating liquid containing at least a resin component (for example, a coating liquid containing a polyimide resin precursor or a polyamideimide resin precursor) is used as a nozzle or Application and casting (formation of a coating film) is performed uniformly on the entire outer surface of the cylinder by a liquid supply device such as a dispenser. Thereafter, the rotation speed is increased to a predetermined speed, and when the predetermined speed is reached, the rotation speed is maintained at a constant speed and rotation is continued for a desired time. And the solvent in a coating film is evaporated at the temperature of about 80-150 degreeC, heating up gradually while rotating. In this process, it is preferable to efficiently circulate and remove atmospheric vapor (such as a volatilized solvent). When a self-supporting film is formed, the mold is transferred to a heating furnace (firing furnace) capable of high-temperature processing, and the temperature is raised stepwise, and finally high-temperature heat processing (firing is performed at about 250 ° C. to 450 ° C. ) To sufficiently imidize or polyamide-imide the polyimide resin precursor or polyamide-imide resin precursor. After sufficiently cooling, the surface layer 12 is subsequently laminated.

  The surface layer 12 uses a paint in which at least a polyrotaxane and a curing agent (crosslinking agent) are dissolved in an organic solvent.

When the polyrotaxane and the curing agent are cross-linked, the mixing ratio of the polyrotaxane and the curing agent is such that the equivalent ratio of the reactive group of the curing agent that reacts with the OH group of the polyrotaxane and the OH group is reactive group / OH group = 0.5 to 3.0. It is preferable to adjust so that. More preferably, the equivalent ratio is adjusted so that reactive groups / OH groups = 1.0 to 1.2. For example, when the curing agent is an isocyanate, the blending ratio of the polyrotaxane and the isocyanate is preferably adjusted so that NCO / OH = 0.5 to 3.0. More preferably, the equivalent ratio is adjusted by NCO / OH = 1.0 to 1.2.
If the equivalent ratio is less than 0.5, it is difficult to sufficiently perform crosslinking, and it may be difficult to maintain the shape of the crosslinked product. On the other hand, if the equivalent ratio is larger than 3.0, the crosslinked product becomes too hard, and the flexibility as the surface layer may be impaired.

  The surface layer can be produced by applying the coating material on the base layer and then drying and curing (crosslinking) the solvent. As with the base layer, existing coating methods such as spiral coating, die coating, roll coating, or spray coating can be applied as with the base layer, but as with the base layer, a cylindrical metal mold is slowly rotated. Then, coating and casting (forming a coating film) are performed uniformly on the entire outer surface of the cylinder by a liquid supply device such as a nozzle or a dispenser. Subsequently, leveling is performed by maintaining a predetermined rotation speed and drying temperature. During rotation, heating may be performed as necessary. A seamless belt can be obtained by such a production method.

  It should be noted that a resistance adjuster for adjusting electrical characteristics to the selected material, a flame retardant for obtaining flame retardancy, an antioxidant, a reinforcing agent, a filler, a vulcanization accelerator, and a plasticizer as necessary. You may perform the mixing | blending which contained materials, such as these suitably.

  The surface coating composition can be made into a crosslinked product by heating. The heating temperature is preferably 130 ° C to 220 ° C, more preferably 140 ° C to 200 ° C, and the crosslinking time is preferably 30 seconds to 5 hours. As a heating method, a known method such as press heating, steam heating, oven heating, hot air heating or the like may be appropriately selected. Further, after cross-linking once, post-cross-linking may be performed in order to surely cross-link to the inside of the cross-linked product. Post-crosslinking is preferably performed for 1 to 48 hours, although it varies depending on the heating method, crosslinking temperature, shape, and the like. What is necessary is just to select the heating method and heating temperature at the time of post-crosslinking suitably.

  Further, the film thickness of the surface layer is preferably 30 μm to 300 μm, more preferably 50 μm to 200 μm. When the thickness is 30 μm or more, the image quality for a paper type having surface irregularities is sufficient. On the other hand, when the thickness is 300 μm or less, the film becomes heavier due to the increased weight of the film, the warpage increases, the running performance becomes unstable, and the bending at the roller curvature for stretching the belt. This is preferable because cracks do not easily occur. In addition, as a measuring method of the said thickness, a cross section can be measured with a scanning microscope (SEM).

<Lubricant>
Next, the lubricant 13 will be described. The lubricant used in the present invention contains a mixture of zinc stearate and zinc palmitate, or contains calcium stearate. Since these adhere to the surface of the intermediate transfer body, the toner releasability can be improved, a high transfer rate can be realized, and the friction coefficient between the surface layer and the cleaning blade can be reduced to achieve high cleaning performance. it can.

  In particular, it is more preferable to use a mixture of zinc stearate and zinc palmitate from the viewpoint that a high transfer rate and a high cleaning property can be realized with a small amount of lubricant consumption. The reason for this is that when the process of applying zinc stearate onto the intermediate transfer member is observed, the block-like zinc stearate is scraped with a brush to be pulverized and stretched with a blade. If the linear velocity of the wire becomes faster, the method of stretching the zinc stearate may not catch up. However, by adding zinc palmitate, which has a lower molecular weight than zinc stearate, to the zinc stearate, even if the linear transfer speed of the intermediate transfer body is high, the lubricant (zinc stearate and zinc palmitate) on the intermediate transfer body Is stretched with a blade, and the intermediate transfer member can be sufficiently covered.

  Zinc stearate and zinc palmitate are both fatty acid metal salts, but the fatty acid portion has 18 carbon atoms in stearic acid and 16 carbon atoms in palmitic acid. For this reason, zinc stearate and zinc palmitate are similar in structure and properties and are compatible with each other and behave as the same material. Since zinc palmitate has a lower melting point than zinc stearate, if a certain amount or more of zinc palmitate is contained in zinc stearate, the lubricant is easily stretched by the blade.

When the zinc stearate and zinc palmitate are used in combination as the lubricant of the present invention, the average value of the total amount of zinc stearate and zinc palmitate adhered to the surface of the intermediate transfer member is preferably 0.3 to 3.0 μg / cm ² , more preferably 0.5 to 1.5 μg / cm ² .

If the average value of the total amount of zinc stearate and zinc palmitate adhering to the intermediate transfer member is less than 0.3 μg / cm ² , it may not be sufficient as the ability to reduce the friction coefficient when blade cleaning the intermediate transfer member. In some cases, high cleaning performance cannot be realized. When the amount of lubricant on the intermediate transfer member exceeds 3.0 μg / cm ² , the toner components easily adhere to the intermediate transfer member, and a high transfer rate is achieved. Since it may become impossible, it is not preferable.

  When using a combination of zinc stearate and zinc palmitate as the lubricant of the present invention, the mixing ratio of zinc stearate and zinc palmitate in the lubricant is preferably 75:25 to 40:60 (mass ratio), 66: 34-40: 60 (mass ratio) is more preferable.

In addition, when calcium stearate is used as the lubricant of the present invention, the amount of calcium stearate adhering to the surface of the intermediate transfer member is 0. 0 as in the case of using a combination of zinc stearate and zinc palmitate as the lubricant. It is preferable that it is 3-3.0 microgram / cm < ² >.

  The lubricant of the present invention may contain boron nitride and filler as other components together with those containing a mixture of zinc stearate and zinc palmitate and those containing calcium stearate.

  Lubricant contains a mixture of zinc stearate and zinc palmitate and calcium stearate (specific metal soap), and boron nitride that does not change its characteristics even when discharged. Lubrication due to discharge deterioration of specific metal soap Can compensate for the decline in sex.

  In the case where the lubricant contains boron nitride together with a specific metal soap, the lubricant supplied for forming the lubricating layer in the lubricant supply means is a specific metal soap with a mixing ratio of the specific metal soap and boron nitride in a mass ratio: Boron nitride is preferably in the range of 70:30 to 95: 5. When the ratio of the specific metal soap / boron nitride is less than 70/30, it may be difficult to form a protective layer mainly composed of the specific metal soap, or a large amount of boron nitride may wear the cleaning blade. When the ratio of the specific metal soap / boron nitride exceeds 95/5, the amount of boron nitride on the intermediate transfer member or the cleaning blade decreases, and it becomes difficult to form an effective protective layer.

  When the lubricant contains boron nitride together with a specific metal soap, it preferably contains fine particles serving as a filler. By containing a filler together with boron nitride, it plays a role of scraping off boron nitride adhering too much on the intermediate transfer member. The filler contained together with boron nitride is not particularly limited as long as it does not impair the object of the invention.For example, aluminum oxide (alumina), silicon oxide, titanium oxide, zirconium oxide, oxide Organic fine particles such as metal oxide fine particles such as cerium, strontium titanate, magnesium aluminate metasilicate, metal double oxide fine particles, silicone resin particles, and silicone rubber particles can be used. Among these, alumina particles are preferable in terms of stability, hardness, availability of fine particles having various particle shapes, and the like.

  Lubricants containing metals and boron nitride, such as metal soaps typified by zinc stearate, use ICP (Inductively Coupled Plasma) emission spectroscopic analysis, ICP mass as a method to determine the amount of lubricant adhered to the intermediate transfer member. There is an analysis, and there is a method for obtaining the adhesion amount from the concentration of the metal element in the unit area of the intermediate transfer member.

<Lubricant supply means>
As the lubricant supply means, any lubricant that contains a mixture of zinc stearate and zinc palmitate or that contains calcium stearate can be attached to the surface of the intermediate transfer member. Lubricant supply means can be used. As the lubricant supply means, it is preferable that the lubricant is adhered by a method of scraping the lubricant with a brush and stretching it with a blade.
In the present invention, the intermediate transfer member can be attached to the surface layer surface of the intermediate transfer member by the lubricant supplying means in the image forming process, but the lubricant is attached to the surface layer surface of the intermediate transfer member in advance at the initial stage. It is necessary to be. As a method of attaching the lubricant to the surface layer surface of the intermediate transfer member in advance, after the intermediate transfer member having no lubricant attached to the surface layer surface is incorporated into the image forming apparatus, the lubricant supplying means of the image forming device is operated in advance. And a method of applying a lubricant, and a method of applying a lubricant when producing an intermediate transfer member.

<Image forming apparatus>
The image forming apparatus of the present invention includes an image carrier that can form a latent image and can carry a toner image, a developing unit that develops the latent image formed on the image carrier with toner, and a developing unit that develops the latent image. An intermediate transfer member on which the toner image formed is primarily transferred, transfer means for secondary transfer of the toner image carried on the intermediate transfer member to a recording medium, and lubrication for supplying a lubricant to the surface of the intermediate transfer member It has an agent supply means, and further has other means appropriately selected as necessary, for example, a static elimination means, a cleaning means, a recycling means, a control means and the like.
In this case, it is preferable that the image forming apparatus is a full-color image forming apparatus in which a plurality of image carriers having developing units for respective colors are arranged in series.

The seamless belt used in the belt constituting unit provided in the image forming apparatus according to the present invention will be described in detail below with reference to a schematic diagram of the relevant part. The schematic diagram is an example, and the present invention is not limited to this.
FIG. 3 is a schematic view of a main part for explaining an image forming apparatus equipped with an intermediate transfer member, which is a seamless belt obtained by the manufacturing method according to the present invention, as a belt member.
The intermediate transfer unit 500 including the belt member shown in FIG. 3 includes an intermediate transfer belt 501 that is an intermediate transfer member stretched around a plurality of rollers. Around the intermediate transfer belt 501 are a secondary transfer bias roller 605 that is a secondary transfer charge applying unit of the secondary transfer unit 600, a belt cleaning blade 504 that is an intermediate transfer member cleaning unit, and a lubricant that is a lubricant supply unit. A lubricant application brush 505 or the like that is an application member is disposed so as to face each other.

  A position detection mark (not shown) is provided on the outer peripheral surface or the inner peripheral surface of the intermediate transfer belt 501. However, on the outer peripheral surface side of the intermediate transfer belt 501, it is necessary to devise a position detection mark that avoids the passing area of the belt cleaning blade 504, which may be difficult to arrange. A position detection mark may be provided on the inner peripheral surface side of the intermediate transfer belt 501. An optical sensor 514 serving as a mark detection sensor is provided at a position between the primary transfer bias roller 507 and the belt driving roller 508 where the intermediate transfer belt 501 is bridged.

  The intermediate transfer belt 501 includes a primary transfer bias roller 507, a belt driving roller 508, a belt tension roller 509, a secondary transfer counter roller 510, a cleaning counter roller 511, and a feedback current detection roller 512, which are primary transfer charge applying units. It is stretched around. Each roller is formed of a conductive material, and each roller other than the primary transfer bias roller 507 is grounded. The primary transfer bias roller 507 is applied with a transfer bias controlled to a predetermined current or voltage according to the number of superimposed toner images by a primary transfer power source 801 controlled at a constant current or voltage. ing.

The intermediate transfer belt 501 is driven in the arrow direction by a belt driving roller 508 that is driven to rotate in the arrow direction by a drive motor (not shown).
The intermediate transfer belt 501 as a belt member is usually a semiconductor or an insulator and has a single layer or a multilayer structure. However, in the present invention, the intermediate transfer belt 501 has a laminated structure including at least a base layer and a surface layer. It is preferably used, thereby improving durability and realizing excellent image formation. Further, the intermediate transfer belt is set to be larger than the maximum sheet passing size in order to superimpose toner images formed on the photosensitive drum 200 as an image carrier.

  A secondary transfer bias roller 605 serving as a secondary transfer unit is attached to and separated from a belt outer peripheral surface of the intermediate transfer belt 501 in a portion stretched around the secondary transfer counter roller 510 by a contact / separation mechanism, which will be described later. It is configured to be able to contact and separate. The secondary transfer bias roller 605 is disposed so as to sandwich the transfer paper P, which is a recording medium, between the portion of the intermediate transfer belt 501 stretched around the secondary transfer counter roller 510 and a constant current. A transfer bias having a predetermined current is applied by a secondary transfer power source 802 to be controlled.

  The registration roller 610 feeds the transfer sheet P, which is a transfer material, between the secondary transfer bias roller 605 and the intermediate transfer belt 501 stretched around the secondary transfer counter roller 510 at a predetermined timing. The secondary transfer bias roller 605 is in contact with a cleaning blade 608 as a cleaning unit. The cleaning blade 608 is for removing the adhering matter adhering to the surface of the secondary transfer bias roller 605 for cleaning.

  In the color copying machine having such a configuration, when an image forming cycle is started, the photosensitive drum 200 is rotated in a counterclockwise direction indicated by an arrow by a drive motor (not shown), and Bk ( Black) toner image formation, C (cyan) toner image formation, M (magenta) toner image formation, and Y (yellow) toner image formation are performed. The intermediate transfer belt 501 is rotated clockwise by the belt driving roller 508 as indicated by an arrow. As the intermediate transfer belt 501 rotates, the primary transfer of the Bk toner image, the C toner image, the M toner image, and the Y toner image is performed by the transfer bias by the voltage applied to the primary transfer bias roller 507. Finally, the respective toner images are formed on the intermediate transfer belt 501 in the order of Bk, C, M, and Y.

For example, the Bk toner image formation is performed as follows.
In FIG. 3, a charging charger 203 uniformly charges the surface of the photosensitive drum 200 to a predetermined potential with a negative charge by corona discharge. The timing is determined based on the belt mark detection signal, and raster exposure with laser light is performed based on the Bk color image signal by a writing optical unit (not shown). When this raster image is exposed, the charge proportional to the exposure light amount disappears in the exposed portion of the surface of the photosensitive drum 200 that is initially uniformly charged, and a Bk electrostatic latent image is formed. When the negatively charged Bk toner on the developing roller of the Bk developing machine 231K comes into contact with this Bk electrostatic latent image, the toner does not adhere to the remaining portion of the photosensitive drum 200, and the charge is not charged. The toner is attracted to the nonexposed portion, that is, the exposed portion, and a Bk toner image similar to the electrostatic latent image is formed.

  The Bk toner image formed on the photosensitive drum 200 in this manner is primarily transferred onto the belt outer peripheral surface of the intermediate transfer belt 501 that is rotating at a constant speed while being in contact with the photosensitive drum 200. Some untransferred residual toner remaining on the surface of the photoreceptor drum 200 after the primary transfer is cleaned by the photoreceptor cleaning device 201 in preparation for reuse of the photoreceptor drum 200. On the photosensitive drum 200 side, the process proceeds to the C image forming process after the Bk image forming process, and reading of C image data by a color scanner starts at a predetermined timing. By writing laser light with the C image data, the photosensitive drum A C electrostatic latent image is formed on the surface of 200.

  Then, after the rear end portion of the previous Bk electrostatic latent image passes and before the front end portion of the C electrostatic latent image arrives, the revolver developing unit 230 is rotated, and the C developing machine 231C develops. The C electrostatic latent image is developed with C toner. Thereafter, the development of the C electrostatic latent image area is continued. When the rear end of the C electrostatic latent image passes, the revolver developing unit is rotated in the same manner as in the case of the previous Bk developing machine 231K. The M developing machine 231M is moved to the developing position. This is also completed before the leading edge of the next Y electrostatic latent image reaches the developing position. Note that the M and Y image forming steps are the same as the Bk and C steps described above because the operations of reading color image data, forming an electrostatic latent image, and developing are the same as those described above. Reference numeral 231Y denotes a Y developing machine.

The Bk, C, M, and Y toner images sequentially formed on the photosensitive drum 200 in this manner are sequentially aligned on the same surface on the intermediate transfer belt 501 and primarily transferred. As a result, a toner image having a maximum of four colors superimposed on the intermediate transfer belt 501 is formed. On the other hand, at the time when the image forming operation is started, the transfer paper P is fed from a paper feed unit such as a transfer paper cassette or a manual feed tray, and is waiting at the nip of the registration roller 610.
When the leading edge of the toner image on the intermediate transfer belt 501 reaches the secondary transfer portion where the nip is formed by the intermediate transfer belt 501 stretched around the secondary transfer counter roller 510 and the secondary transfer bias roller 605. Then, the registration roller 610 is driven so that the leading edge of the transfer paper P coincides with the leading edge of the toner image, and the transfer paper P is conveyed along the transfer paper guide plate 601, and the transfer paper P and the toner image are transferred. Resist alignment is performed.

  In this way, when the transfer paper P passes through the secondary transfer portion, the four-color superimposed toner image on the intermediate transfer belt 501 is transferred by the transfer bias applied by the secondary transfer power source 802 to the secondary transfer bias roller 605. Are collectively transferred (secondary transfer) onto the transfer paper P. After the transfer paper P is conveyed along the transfer paper guide plate 601 and passed through a portion facing the transfer paper neutralization charger 606 composed of a static elimination needle disposed on the downstream side of the secondary transfer portion, the transfer paper P is discharged. Then, the toner is fed toward the fixing device 270 by the belt conveyance device 210 which is a belt component. Then, after the toner image is melted and fixed at the nip portions of the fixing rollers 271 and 272 of the fixing device 270, the transfer paper P is sent out of the apparatus main body by a discharge roller (not shown), and is stacked face up on a copy tray (not shown). Is done. Note that the fixing device 270 may be configured to include a belt component if necessary.

  On the other hand, the surface of the photosensitive drum 200 after the belt transfer is cleaned by the photosensitive member cleaning device 201 and is uniformly discharged by the discharging lamp 202. Further, residual toner remaining on the outer peripheral surface of the intermediate transfer belt 501 after the toner image is secondarily transferred to the transfer paper P is cleaned by the belt cleaning blade 504. The belt cleaning blade 504 is configured to be brought into contact with and separated from the belt outer peripheral surface of the intermediate transfer belt 501 at a predetermined timing by a cleaning member separating and contacting mechanism (not shown).

  On the upstream side of the belt cleaning blade 504 in the movement direction of the intermediate transfer belt 501, a toner seal member 502 that is in contact with and away from the outer peripheral surface of the intermediate transfer belt 501 is provided. The toner seal member 502 receives the falling toner that has fallen from the belt cleaning blade 504 when cleaning the residual toner, and prevents the falling toner from being scattered on the transfer path of the transfer paper P. The toner seal member 502 is brought into contact with and separated from the belt outer peripheral surface of the intermediate transfer belt 501 together with the belt cleaning blade 504 by the cleaning member separating and contacting mechanism.

  The lubricant 506 scraped by the lubricant application brush 505 is applied to the outer peripheral surface of the intermediate transfer belt 501 from which the residual toner has been removed in this way. The lubricant 506 is made of, for example, a solid body such as a mixture of zinc stearate and zinc palmitate and calcium stearate, and is disposed so as to come into contact with the lubricant application brush 505. Further, residual charges remaining on the outer peripheral surface of the intermediate transfer belt 501 are removed by a neutralizing bias applied by a belt neutralizing brush (not shown) that is in contact with the outer peripheral surface of the intermediate transfer belt 501. Here, the lubricant application brush 505 and the belt neutralizing brush are brought into contact with and separated from the belt outer peripheral surface of the intermediate transfer belt 501 at a predetermined timing by respective contact and separation mechanisms (not shown). .

Here, at the time of repeat copy, the operation of the color scanner and the image formation on the photosensitive drum 200 are performed at a predetermined timing following the first color (Y) image formation process of the first sheet and the first color of the second sheet. The process proceeds to the image forming process (Bk). Further, the intermediate transfer belt 501 has a second Bk toner in the area cleaned by the belt cleaning blade 504 on the outer peripheral surface of the belt following the batch transfer process of the first four-color superimposed toner image to the transfer paper. The image is first transferred. After that, the operation is the same as the first sheet. The above is a copy mode for obtaining a four-color full-color copy. In the three-color copy mode and the two-color copy mode, the same operation as described above is performed for the designated color and the number of times. In the case of the single color copy mode, only the predetermined color developing machine of the revolver developing unit 230 is set in the developing operation state until the predetermined number of sheets is completed, and the belt cleaning blade 504 is kept in contact with the intermediate transfer belt 501. The copy operation is performed in the state.
In FIG. 3, reference numeral 70 denotes a static elimination roller, 204 denotes a potential sensor, 205 denotes an image density sensor, 503 denotes a charging charger, 513 denotes a toner image, and L denotes laser light (emitted from laser exposure means).

In the above-described embodiment, the copying machine including only one photosensitive drum 1 has been described. However, the present invention includes a plurality of photosensitive drums as shown in a configuration example in a schematic diagram of a main part in FIG. The present invention can also be applied to an image forming apparatus arranged side by side along one intermediate transfer belt formed of a seamless belt.
The schematic diagram of the main part of FIG. 4 shows an example of a full-color image forming apparatus in which a plurality of image carriers are arranged in parallel along the intermediate transfer belt of the present invention. That is, FIG. 4 shows a four-drum type digital color printer having four photosensitive drums 21BK, 21Y, 21M, and 21C for forming toner images of four different colors (black, yellow, magenta, and cyan). A configuration example is shown.

  In FIG. 4, the printer body 10 includes an image writing unit 12, an image forming unit 13, and a paper feeding unit 14 for performing color image formation by an electrophotographic method. Based on the image signal, the image processing unit converts the image into black (BK), magenta (M), yellow (Y), and cyan (C) color signals for image formation and transmits them to the image writing unit 12. To do. The image writing unit 12 is a laser scanning optical system including, for example, a laser light source, a deflector such as a rotary polygon mirror, a scanning imaging optical system, and a mirror group. Image writing corresponding to each color signal is performed on image carriers (photoconductors) 21BK, 21M, 21Y, and 21C that have a writing optical path and are provided for each color of the image forming unit 13.

  The image forming unit 13 includes photoconductors 21BK, 21M, 21Y, and 21C that are image carriers for black (BK), magenta (M), yellow (Y), and cyan (C). As each photoconductor for each color, an OPC photoconductor is usually used. Around the photoreceptors 21BK, 21M, 21Y, and 21C, there are a charging device, an exposure unit for laser light from the writing unit 12, and developing devices 20BK, 20M, 20Y for black, magenta, yellow, and cyan, respectively. 20C, primary transfer bias rollers 23BK, 23M, 23Y, and 23C as primary transfer means, a cleaning device (not shown), and a photosensitive member static elimination device (not shown) are arranged. The developing devices 20BK, 20M, 20Y, and 20C use a two-component magnetic brush developing system. The intermediate transfer belt 22, which is a belt component, is interposed between the photosensitive members 21BK, 21M, 21Y, and 21C and the primary transfer bias rollers 23BK, 23M, 23Y, and 23C, and is formed on the photosensitive members. The toner images of each color are sequentially superimposed and transferred.

  On the other hand, the transfer paper P is fed from the paper feed unit 14 and then carried by the transfer conveyance belt 50, which is a belt component, via the registration roller 16. When the intermediate transfer belt 22 and the transfer conveyance belt 50 come into contact, the toner image transferred onto the intermediate transfer belt 22 is subjected to secondary transfer (collective transfer) by a secondary transfer bias roller 60 as a secondary transfer unit. ) As a result, a color image is formed on the transfer paper P. The transfer paper P on which the color image is formed is conveyed to the fixing device 15 by the transfer conveying belt 50, and after the image transferred by the fixing device 15 is fixed, it is discharged out of the printer main body.

  The residual toner that is not transferred during the secondary transfer and remains on the intermediate transfer belt 22 is removed from the intermediate transfer belt 22 by the belt cleaning member 25. A lubricant application device 27 is disposed on the downstream side of the belt cleaning member 25. The lubricant application device 27 includes a solid lubricant and a conductive brush that rubs the intermediate transfer belt 22 to apply the solid lubricant. The conductive brush is always in contact with the intermediate transfer belt 22 and applies a solid lubricant to the intermediate transfer belt 22. The solid lubricant has an effect of improving the cleaning property of the intermediate transfer belt 22, preventing the occurrence of filming, and improving the durability. In FIG. 4, reference numeral 26 denotes a driving roller, and 70 denotes a bias roller.

Further, the present invention relates to the following intermediate transfer member [1], and includes the following [2] to [4] as embodiments.
[1] An image carrier that can form a latent image and can carry a toner image; a developing unit that develops the latent image formed on the image carrier with toner; and a toner image developed by the developing unit. An intermediate transfer member that is primarily transferred; a transfer unit that secondarily transfers a toner image carried on the intermediate transfer member to a recording medium; and a lubricant supply unit that supplies a lubricant to the surface of the intermediate transfer member. An image forming apparatus comprising:
The intermediate transfer member has a laminated structure comprising at least a base layer and a surface layer,
The surface layer includes at least a cyclic molecule, a linear molecule that includes the cyclic molecule in a skewered manner, and a blocking group that is disposed at both ends of the linear molecule and prevents the cyclic molecule from being detached. Including a crosslinked polyrotaxane,
The lubricant comprises a mixture of zinc stearate and zinc palmitate, or calcium stearate;
An image forming apparatus, wherein the lubricant adheres to the surface of the intermediate transfer member.
[2] The image forming apparatus according to [1], wherein the lubricant includes a mixture of zinc stearate and zinc palmitate.
[3] The image forming apparatus according to [1] or [2], wherein the intermediate transfer member is a seamless belt.
[4] Any of the above [1] to [3], wherein the image forming apparatus is a full-color image forming apparatus, and a plurality of image carriers having developing units for respective colors are arranged in series. The image forming apparatus described in 1.

EXAMPLES Hereinafter, the present invention will be described more specifically based on examples. However, the present invention is not limited by these examples, and these examples are appropriately modified without departing from the gist of the present invention. Is also within the scope of the present invention.
In addition, the film thickness of each of the base layer and the surface layer of the belt was measured by observing cross sections at arbitrary 10 positions with a scanning electron microscope (SEM), and taking the average value. Unless otherwise specified, “parts” means “parts by mass”. Moreover, solid content ratio is shown on a mass basis.

<Preparation of Intermediate Transfer Belt 1>
A base layer coating solution was prepared as follows, and a seamless belt base layer was prepared using this coating solution.
"Preparation of base layer coating solution A"
First, a polyimide varnish mainly composed of a polyamic acid which is a polyimide resin precursor (U-varnish A and U-varnish S mixed at a solid content ratio of 6: 4; manufactured by Ube Industries Co., Ltd.) is preliminarily processed with a beads mill. A dispersion of carbon black (Special Black 4; Orion Engineered Carbons) dispersed in methyl-2-pyrrolidone is prepared so that the carbon black content is 17% by mass of the polyamic acid solid content, and mixed well with stirring. A base layer coating solution A was prepared.

“Preparation of polyimide base layer A”
Next, a metal cylindrical support whose outer surface is 375 mm in length and 340 mm in length is roughened by blasting is used as a mold, and the coating is performed while rotating the cylinder at 50 rpm (times / minute). The working liquid was applied with a dispenser so as to be uniformly cast on the outer surface of the cylinder. When the predetermined amount was completely poured and the coating film was spread evenly, the number of revolutions was increased to 100 rpm, introduced into a hot air circulating dryer, gradually heated to 110 ° C. and heated for 60 minutes. Further, the temperature is raised and heated at 200 ° C. for 20 minutes, the rotation is stopped, and it is slowly cooled to take out the cylindrical mold on which the formed film is formed, and this is introduced into a heating furnace (firing furnace) capable of high-temperature processing. Specifically, the temperature was raised to 360 ° C. and heat treatment (firing) was performed for 60 minutes. It was sufficiently cooled to obtain a belt-like polyimide base layer A having a film thickness of 60 μm.

"Preparation of surface coating liquid A"
First, a polyrotaxane “Celum Superpolymer SH3400P (Advanced Soft Materials)”, which is a cyclodextrin having a polyethylene glycol as a linear molecule, an adamantane group as a blocking group, and a hydroxylpropyl group as a cyclic molecule, is dissolved in cyclohexanone. Then, Duranate TPA-B80E (Asahi Kasei Chemical) [block isocyanate], which is a hexamethylene diisocyanate polyisocyanate, is added and adjusted so that the NCO (reactive group of curing agent) / OH equivalent ratio is 1.05. Surface layer coating solution A was prepared.
The chemical name of the polyrotaxane “Celum Superpolymer SH3400P” is “modified polyrotaxane-graft-polycaprolactone (CAS No. 928045-45-8)”. (Linear molecule is polyethylene glycol, blocking group is adamantane group, cyclic molecule is hydroxyl group-containing α-cyclodextrin)

Next, the surface coating liquid A is continuously applied from the nozzle onto the polyimide base layer while rotating the cylindrical support on which the polyimide base layer A prepared in advance is prepared. It was moved to the axis method of the support while being discharged, and coated in a spiral shape. The coating amount was such that the final surface layer thickness was 100 μm. Thereafter, the cylindrical support coated with the surface layer coating liquid A is put into a hot air circulating dryer while rotating as it is, heated to 150 ° C. at a temperature rising rate of 3 ° C./min, and heated for 30 minutes. [Intermediate transfer belt A] was obtained.
[Intermediate transfer belt A] is mounted on an image MPC7501 (manufactured by Ricoh) (apparatus as shown in FIG. 4) provided with a lubricant supply means, and a lubricant application apparatus (lubricant supply means) is operated to make zinc stearate. And a mixture of zinc palmitate (60% by weight zinc stearate, 40% by weight zinc palmitate) are applied to the intermediate transfer belt A for 3 minutes, and a lubricant is adhered to the surface of the intermediate transfer belt 1 [intermediate transfer belt 1]. Obtained. The thickness of the lubricant layer is set to be about 15 nm when applied for 3 minutes.

<Preparation of Intermediate Transfer Belt 2>
In the production of the intermediate transfer belt 1, an intermediate transfer belt 2 was obtained by using calcium stearate as a lubricant for the intermediate transfer belt A instead of a mixture of zinc stearate and zinc palmitate.

<Preparation of intermediate transfer belt 3>
In the production of the intermediate transfer belt 1, in place of Duranate TPA-B80E (Asahi Kasei Chemical) [block isocyanate], which is a hexamethylene diisocyanate polyisocyanate used in the surface coating liquid, Duranate 17B, which is a hexamethylene diisocyanate polyisocyanate. [Intermediate transfer belt 3] was obtained in the same manner as in the production of intermediate transfer belt 1 except that 60 (Asahi Kasei Chemical) [block isocyanate] was used.

<Preparation of Intermediate Transfer Belt 4>
In the production of the intermediate transfer belt 1, instead of Duranate TPA-B80E (Asahi Kasei Chemical) [block isocyanate], which is a hexamethylene diisocyanate polyisocyanate used for the surface coating liquid, Takenate D-, which is a hexamethylene diisocyanate polyisocyanate. [Intermediate transfer belt 4] was obtained in the same manner as in the production of intermediate transfer belt 1 except that 177N (Mitsui Chemicals) was used.

<Preparation of intermediate transfer belt 5>
In the production of the intermediate transfer belt 1, an intermediate transfer belt 5 was obtained in the same manner as the production of the intermediate transfer belt 1 except that the surface layer was not laminated and the lubricant was not applied.

<Preparation of intermediate transfer belt 6>
"Preparation of acrylic resin prepolymer solution B"
2-hydroxyethyl methacrylate: 60 parts, 2- (perfluorohexyl) ethyl acrylate: 40 parts, azobisisobutyronitrile (AIBN, polymerization initiator): 6 parts, methyl ethyl ketone: 100 parts in a dropping funnel, nitrogen The mixture was added dropwise to 100 parts of methyl ethyl ketone heated to 80 ° C. under reflux over 3 hours with stirring and polymerized. Further, a liquid composed of 50 parts of methyl ethyl ketone and 2 parts of AIBN was added dropwise over 1 hour, and further stirred for 1 hour to complete the reaction. During the reaction, the temperature was kept at 80 ° C. and stirring was continued. The reaction solution was concentrated to adjust the concentration to 40%, and an acrylic resin prepolymer solution B in which the acrylic resin prepolymer was dissolved in a solvent was synthesized.

Acrylic resin prepolymer solution B: 100 parts, polyimide solution (DIC, product name: Unidic V-8000, concentration: 40%): 30 parts, isocyanate solution (Asahi Kasei Chemicals, product name: Duranate TPA-B80E, effective (NCO%: 12.5%): 62 parts of acrylic resin prepolymer solution B and polyimide solution were first mixed, then an isocyanate solution was further added and defoamed for 10 minutes under reduced pressure. Produced.
While rotating the cylindrical support on which the polyimide base layer B produced by the same method as the polyimide base layer A produced in the intermediate transfer belt 1 produced above was rotated at 50 rpm (times / minute), the surface coating liquid B was produced. On the polyimide base layer B, the surface layer coating solution B was applied by a dispenser so as to be uniformly cast on the outer surface of the cylinder. When the predetermined amount was completely flowed and the coating film was spread evenly, the number of rotations was increased to 100 rpm, introduced into a hot air circulating dryer, gradually heated to 80 ° C. and heated for 60 minutes. Further, the temperature was raised and heat-cured at 150 ° C. for 60 minutes, and the rotation was stopped and cooled sufficiently to obtain [Intermediate transfer belt 6]. By the said method, it was confirmed that the obtained resin layer sample contains the reaction material of a polyurethane and a polyimide.

<Preparation of intermediate transfer belt 7>
In the production of the intermediate transfer belt 1, an intermediate transfer belt 7 was obtained in the same manner as the production of the intermediate transfer belt 1 except that the surface layer was not laminated.

<Preparation of intermediate transfer belt 8>
In the production of the intermediate transfer belt 6, a product produced in the same manner as the [intermediate transfer belt 6] is mounted on an imagino MPC7501 (Ricoh) equipped with a lubricant supply means, and a lubricant application device (lubricant supply means) is operated. Similarly to the production of the intermediate transfer belt 1, a mixture of zinc stearate and zinc palmitate was applied to the intermediate transfer belt A for 3 minutes to obtain [Intermediate transfer belt 8].

<Preparation of intermediate transfer belt 9>
In the production of the intermediate transfer belt 1, [Intermediate transfer belt 9] was obtained in the same manner as the production of the intermediate transfer belt 1 except that no lubricant was applied.

<Preparation of Intermediate Transfer Belt 10>
In the production of the intermediate transfer belt 1, the intermediate transfer belt 10 was obtained by using mica instead of the mixture of zinc stearate and zinc palmitate as the lubricant for the intermediate transfer belt A.
<Preparation of Intermediate Transfer Belt 11>
In the production of the intermediate transfer belt 1, as the lubricant for the intermediate transfer belt A, [intermediate transfer belt 11] was obtained by using talc instead of a mixture of zinc stearate and zinc palmitate.

<Examples 1-4, Comparative Examples 1-7>
Table 1 shows the composition of the surface coating solution of the intermediate transfer belt, the presence or absence of the lubricant, and the type thereof in Examples 1 to 4 and Comparative Examples 1 to 7.

The intermediate transfer belts 1 to 11 were mounted on an imagio MPC7501 (Ricoh). As the paper, (1) plain paper TYPE 6200 (Ricoh), (2) rippled paper FC Japanese paper (Ricoh), and (3) FOX RIVER SELECT SCRIPT WRITING (FOX RIVER) were used to output 1000 sheets each.
However, in the intermediate transfer belt 5, the intermediate transfer belt 6, and the intermediate transfer belt 9 of Comparative Example 1, Comparative Example 2, and Comparative Example 5, no lubricant is applied to the belt. On the other hand, the intermediate transfer belts 1 to 4, the intermediate transfer belt 7, the intermediate transfer belt 8, the intermediate transfer belt 10, and the intermediate transfer of Examples 1 to 4, Comparative Example 3, Comparative Example 4, Comparative Example 6, and Comparative Example 7. In the belt 11, the same lubricant as that applied to the surface layer before application is applied with a lubricant application brush and output.
Sasakinami FC Japanese paper is a rough paper with an uneven pattern in Japanese paper style, and image density unevenness and white spots are likely to occur. FOX RIVER SELECT SCRIPT WRITING is a so-called multi-paper powder paper that tends to produce paper dust, causing image blurring. Adhesion (spotted density unevenness) is likely to occur.
The images (1) and (2) were output as a blue solid image of cyan and magenta, and the paper (3) was output as a halftone image in black only.

As the evaluation, the secondary transfer rate was measured, and the blade cleaning property and abnormal images (density unevenness, white spots, blurring) and filming were evaluated. However, no other evaluation was performed on the filming.
The secondary transfer rate was calculated by the following formula. As the values, average values of 10 sheets from the first sheet to the 10th sheet of each output image were adopted.
Secondary transfer rate (%) = {([toner amount on intermediate transfer belt before transfer (g)] − [toner amount on intermediate transfer belt after transfer (g)]) / [intermediate transfer belt before transfer] Upper toner amount (g)]} × 100
In addition, in the abnormal image evaluation, white spots, density unevenness, and blurring were evaluated on the worst samples among 10 images from the 991st to 1000th output images. ○ is good, Δ is the actual usable level, and × is the unusable level.
On the other hand, the blade cleaning property was evaluated as to whether or not an abnormal image appears when the blade is turned over, and whether or not abnormal noise is generated when the friction coefficient between the blade and the intermediate transfer belt is high. ○ indicates good, Δ indicates cleaning is possible but abnormal noise is generated, and × indicates cleaning is not possible.
The evaluation of the occurrence of filming was made by visually observing the surface of the intermediate transfer body after outputting 1000 sheets of images, where no filming occurred, and x where it occurred.

The results are shown in Table 2.

In Examples 1 to 4, in which the surface layer of the intermediate transfer member contains a crosslinked polyrotaxane and a specific lubricant is supplied to the surface of the surface layer, both transfer performance and cleanability can be achieved.
On the other hand, when the polyimide of Comparative Example 1 is used alone or when the surface layer of Comparative Example 2 is a mixture of polyimide and polyurethane, the surface is hard, so that the followability to rippled paper is low and the uneven transferability is poor. Furthermore, although blade cleaning is possible, abnormal noise sometimes occurred during output. In addition, when the lubricant is supplied to the polyimide of Comparative Example 3 alone, or when the lubricant is supplied to the mixture of polyimide and polyurethane on the surface layer of Comparative Example 4, the blade cleaning property is improved, Since the surface is hard, the followability to rippled paper is low, and the unevenness transfer property is poor. When the surface layer of Comparative Example 5 only contains a crosslinked polyrotaxane, the friction coefficient with the blade was high, so that the blade could not be cleaned well and images could not be output continuously. Filming occurred when mica and talc were used as the lubricants of Comparative Examples 6 and 7.

  As described above, by adopting the configuration of the present invention, it is possible to provide a high-quality electrophotographic apparatus that can realize high transfer performance regardless of the type and surface properties of the transfer medium and that can ensure cleaning performance with a cleaning blade. .

(Reference in FIG. 1)
11 Base layer 12 Surface layer 13 Lubricant (lubricant layer)

(Reference in FIG. 2)
1 Polyrotaxane 2 Linear molecule 3 Cyclic molecule 3A Lipophilic modifying group 4 Blocking group

(Reference in FIG. 3)
P Transfer paper L Laser light 70 Static elimination roller 80 Ground roller 200 Photosensitive drum 201 Photosensitive drum cleaning device 202 Static elimination lamp 203 Charging charger 204 Potential sensor 205 Image density sensor 210 Belt conveying device 230 Revolver developing unit 231Y Y developing machine 231K Bk developing machine 231C C developing machine 231M M developing machine 270 fixing device 271 and 272 fixing roller 500 intermediate transfer unit 501 intermediate transfer belt 502 toner seal member 503 charging charger 504 belt cleaning blade 505 lubricant application brush 506 lubricant 507 primary transfer bias roller 508 Belt drive roller 509 Belt tension roller 510 Secondary transfer counter roller 511 Cleaning counter roller 512 Feedback current detection sensor 513 Toner image 514 Optical sensor 600 Secondary transfer unit 601 Transfer paper guide plate 605 Secondary transfer bias roller 606 Transfer paper neutralization charger 608 Cleaning blade 610 Registration roller 801 Primary transfer power source 802 Secondary transfer power source

(Reference in FIG. 4)
P Transfer paper 10 Printer body 12 Image writing unit 13 Image forming unit 14 Paper feeding unit 15 Fixing device 16 Registration roller 20BK, 20M, 20Y, 20C Developing device 21BK, 21M, 21Y, 21C Photoconductor 22 Intermediate transfer belt 23BK, 23M , 23Y, 23C Primary transfer bias roller 25 Belt cleaning member 26 Drive roller 27 Lubricant coating device 50 Transfer conveyor belt 60 Secondary transfer bias roller 70 Bias roller

Japanese Patent No. 4810673 Japanese Patent No. 4973781 JP 2012-181244 A Japanese Patent No. 4376846 Japanese Patent No. 4376848 Japanese Patent No. 4376849 Japanese Patent No. 4385165 Japanese Patent No. 5071564

Claims (4)

A latent image is formed and an image carrier capable of carrying a toner image; a developing unit that develops the latent image formed on the image carrier with toner; and a toner image developed by the developing unit is primarily transferred. An intermediate transfer body, a transfer means for secondary transfer of a toner image carried on the intermediate transfer body to a recording medium, and a lubricant supply means for supplying a lubricant to the upper surface of the intermediate transfer body. An image forming apparatus comprising:
The intermediate transfer member has a laminated structure comprising at least a base layer and a surface layer,
The surface layer includes at least a cyclic molecule, a linear molecule that includes the cyclic molecule in a skewered manner, and a blocking group that is disposed at both ends of the linear molecule and prevents the cyclic molecule from being detached. Including a crosslinked polyrotaxane,
The lubricant comprises a mixture of zinc stearate and zinc palmitate, or calcium stearate;
An image forming apparatus, wherein the lubricant adheres to the surface of the intermediate transfer member.   The image forming apparatus according to claim 1, wherein the lubricant contains a mixture of zinc stearate and zinc palmitate.   The image forming apparatus according to claim 1, wherein the intermediate transfer member is a seamless belt.   The image forming apparatus according to claim 1, wherein the image forming apparatus is a full-color image forming apparatus, and a plurality of image carriers having developing units for respective colors are arranged in series. .