JP2011118350A - Method and system of electrophotographic intermediate transfer, method and apparatus for forming image - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a long life full-color electrophotographic intermediate transfer method wherein electrical properties are stable, anti-abrasion properties are excellent, image defects, such as void, density unevenness, and color unevenness, are prevented, and a high quality full-color image is formed, is secured and to provide an electrophotographic image forming method using the same, and to provide an electrophotographic intermediate transfer system and an electrophotographic image forming apparatus with the same. <P>SOLUTION: The exposure rate (B/A)×100(%) of an intermediate transfer belt is 30% or less, this exposure rate being calculated from the content A(atm%) of nitrogen obtained by measuring the surface of the intermediate transfer belt by XPS before metal soap is applied, and from the content B (atm%) of nitrogen obtained by measuring the surface of the intermediate transfer belt by XPS after the metal soap is applied for 5 minutes without setting toner and paper. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electrophotographic intermediate transfer method used in an electrophotographic apparatus, an electrophotographic image forming method using the electrophotographic intermediate transfer system, an electrophotographic intermediate transfer system used in the electrophotographic apparatus, and The present invention relates to an electrophotographic image forming apparatus using the electrophotographic intermediate transfer system.

In an electrophotographic apparatus, a seamless belt member is used for various functions and applications in the apparatus. Examples of the seamless belt member include a transfer belt and a paper transport belt.
Further, in recent years, in a full-color electrophotographic apparatus, a toner image of four colors or more formed on a photoreceptor is transferred to an intermediate transfer belt to form a full-color image on the intermediate transfer belt. After that, a seamless belt member is used as an intermediate transfer belt in a system in which the transfer is performed collectively on a transfer medium such as paper.

  The demand for intermediate transfer belts is rapidly increasing due to the progress of full-color copying machines. As the intermediate transfer belt, materials such as thermoplastic resin, thermosetting resin, rubber, and elastomer are used. In the image forming system using the intermediate transfer belt, in order to obtain high speed, a system called a tandem system in which color developing devices for respective colors facing the intermediate transfer belt are arranged in series is the mainstream.

  The intermediate transfer belt used in this tandem system is required to have high strength that can withstand repeated use without causing color misregistration due to deformation during running, and also requires flame resistance. Polyamideimide resin is preferably used. In particular, a polyimide resin is preferably used in terms of creep deformability, durability, and electrical property control.

In the intermediate transfer belt made of polyimide resin, a certain amount of toner remains on the intermediate transfer belt even after the toner image is transferred, so a belt cleaning device for removing such residual toner is necessary.
For removing the residual toner, it is most effective to “rub off” the residual toner by pressing the blade edge of the cleaning blade against the surface of the intermediate transfer belt.
However, the intermediate transfer belt is provided with the electrical characteristics necessary for the transfer of the toner image, but when the image formation over a long period of time is repeated, such electrical characteristics are impaired by the pressure contact of the cleaning blade, There is a problem of shortening the life of the intermediate transfer belt. As a result, an abnormal image due to poor cleaning occurs.

  In addition, as the oilless flow of the fixing process, the toner as a developer often contains wax, and the fixing temperature is lowered due to energy saving, so the toner base is also more easily softened than before. Material has been used. The wax and the toner base are likely to adhere to the intermediate transfer belt, and when image formation is repeated, so-called filming occurs in which the toner component adheres in the form of a film, which degrades the electrical characteristics of the intermediate transfer belt. Furthermore, not only conventional copy paper but also paper for image formation, image formation on paper containing a large amount of fillers such as talc, kaolin and calcium carbonate is required, such as coated paper and printing paper. It has been. However, these paper fillers are likely to adhere from the paper to the intermediate transfer belt during secondary transfer, and filming tends to occur starting from this filler, which tends to cause problems.

  It is known that it is effective to reduce the surface friction coefficient of the intermediate transfer belt in order to reduce damage due to the pressure contact of the cleaning blade and to suppress filming due to toner material and paper filler. In order to reduce the surface friction coefficient, it has been proposed to apply metal soap as a lubricant to the surface of the intermediate transfer belt (see, for example, Patent Documents 1 and 2).

  In fact, these image forming apparatuses can form high-quality images at low speed. However, when the image forming speed is increased and the linear speed of the intermediate transfer belt is increased and image formation is continuously performed, for example, a belt-like abnormal image is likely to occur. This is because the surface friction coefficient becomes higher than the part where the image is present, and the so-called filming occurs in which the toner component and the paper filler adhere to the film. This is due to the occurrence of band-like density unevenness due to a change in the electrical characteristics of the generated location. For this reason, one of the causes of filming is that the amount of metal soap attached is not sufficient.

  For this reason, in order to sufficiently adhere the lubricant onto the surface of the intermediate transfer belt, it is conceivable to control the form of the surface of the intermediate transfer belt. Until now, the surface of the intermediate transfer belt has been polished with abrasive paper, an abrasive, etc. There has been proposed a method for roughening the surface (see, for example, Patent Documents 3 and 4).

The inventors tried to grasp the optimum surface form of the intermediate transfer belt with reference to the methods described in Patent Documents 3 and 4. However, even though there should be enough metal soap on the intermediate transfer belt (the amount of adhesion on the intermediate transfer belt is sufficient), if image formation is performed at a high linear velocity of the intermediate transfer belt, There were locations where ming occurred and where it did not occur.
Therefore, the present inventors have analyzed in detail the intermediate transfer belt where filming occurs and where filming does not occur with an electron microscope, and metal soap is present on the intermediate transfer belt where filming occurs. It was found that there was very little and unevenness in the adhesion of metal soap. In general, it is said that metal soap is stable when it is present in two molecules.
From these facts, it was found that the presence of metal soap is important. Therefore, in order to realize high-quality image formation with the intermediate transfer belt at a high linear velocity, it was considered important to cover the entire surface of the intermediate transfer belt with metal soap.

  The present invention solves the above-mentioned problems of the prior art, has stable electrical characteristics, excellent wear resistance, no abnormal images such as voids, density unevenness, and color unevenness, and provides a high-quality full-color image. To provide a long-life full-color electrophotographic intermediate transfer method to be formed, an electrophotographic image forming method using the same, an electrophotographic intermediate transfer system, and an electrophotographic image forming apparatus using the same Objective.

  In order to ascertain the coverage of the metal soap on the intermediate transfer belt of the metal soap, the present inventors used the XPS (X -ray photoelectron spectroscopy: An attempt was made to define a preferable coverage of the metal soap on the intermediate transfer belt by a method (Patent Documents 5 to 8) obtained by analysis.

  The XPS analysis method can detect all elements other than hydrogen atoms on the extreme surface of the sample. Therefore, when the surface of the photoreceptor coated with zinc stearate is analyzed using XPS, the sensitivity of the surface increases as the zinc stearate coverage increases. When the element ratio of the body approaches the element ratio of zinc stearate and the zinc stearate coverage becomes 100%, the element ratio theoretically matches the element ratio of zinc stearate, and the detected zinc element is saturated Resulting in. That is, when zinc stearate covers the entire surface of the photoreceptor, the ratio of zinc element to all elements detected by XPS is theoretically 2.44 atomic%, based on the ratio of elements other than hydrogen in the molecule of zinc stearate. It becomes. Therefore, the zinc stearate coverage (Zn / 2.44) × 100 (%) can be calculated from this zinc atomic%.

  In addition, when zinc stearate contains a certain amount of zinc palmitate having a slightly smaller molecular length than zinc stearate, the melting point of zinc palmitate is lower than that of zinc stearate. Even if the linear velocity of the belt is high, the metal soap can sufficiently cover the intermediate transfer belt.

  However, when a mixture of zinc stearate and zinc palmitate is used as the metal soap, the above theoretical value of the ratio of zinc element cannot be used, and it is necessary to use the proportion of Zn in the mixture of zinc stearate and zinc palmitate. . However, since the mixing ratio changes slightly depending on the lot at the stage of delivery, it is necessary to grasp the mixing ratio every time it is delivered, which is time consuming and expensive.

Therefore, the present inventors searched for a method that can grasp the coating state of the metal soap on the surface of the intermediate transfer belt regardless of the mixing ratio of the zinc stearate and zinc palmitate of the metal soap. The present inventors have found a method that pays attention to the exposure rate calculated from the reduction rate of the nitrogen element content rate on the surface of the intermediate transfer belt due to the application of metal soap instead of the content rate of.
In the present invention, the intermediate transfer belt contains nitrogen on the surface. Therefore, the exposure rate can be calculated from the decrease rate of the nitrogen element content on the surface of the intermediate transfer belt, and the coverage of the metal soap on the surface of the intermediate transfer belt is calculated by 100− (the exposure rate of the surface of the intermediate transfer belt). Can do.

Further, the present inventors have observed the location where an abnormal image occurs, and found that the manner of generating an abnormal image differs depending on whether the image area of the image to be formed is large or small. For this reason, the application effect of the metal soap, which excludes the influence of the image area size, is evaluated by calculating the coverage ratio without applying image formation and only applying the metal soap on the intermediate transfer belt. can do.
As a result of the evaluation using the above-described calculation method, the present inventors have found that the exposure rate on the surface of the intermediate transfer belt is 30% or less, the metal soap is sufficiently applied in any image formation. It was found that an effect can be obtained.

  That is, in order to solve the above problems, an electrophotographic intermediate transfer method according to the present invention, an electrophotographic image forming method using the same, an electrophotographic intermediate transfer system, and an electrophotographic image using the same Specifically, the forming apparatus has the technical features described in the following (1) to (12).

(1): An intermediate transfer method for electrophotography in which intermediate transfer is performed using an intermediate transfer belt for electrophotography containing nitrogen element on the surface,
Having a metal soap application step of applying metal soap to the electrophotographic intermediate transfer belt,
In the metal soap application step, the content A (atm%) of nitrogen element obtained by measuring the surface of the intermediate transfer belt before application of the metal soap with XPS, and the state where the toner and paper are not present in the metal soap The intermediate transfer belt exposure rate (B / A) × 100 (calculated from the nitrogen element content B (atm%) obtained by measuring the surface of the intermediate transfer belt after XPS for 5 minutes with XPS. %) Is 30% or less, an electrophotographic intermediate transfer method.

(2): The electrophotographic intermediate transfer method according to (1), wherein the metal soap is a mixture of zinc stearate and zinc palmitate.

(3): The electrophotographic intermediate transfer method according to (2), wherein the mixing ratio of the zinc stearate and the zinc palmitate is 73:27 to 45:55 by weight ratio. It is.

(4): The intermediate transfer belt has a linear protrusion on the surface,
The intermediate transfer method for electrophotography according to any one of (1) to (3), wherein the convex portion has a height of 0.01 μm to 1 μm and a width of 0.5 μm to 5 μm. It is.

(5): the image forming region of the intermediate transfer belt is surrounded by a line-shaped convex portion, it is a plurality of small regions divided, and each area of the divided small regions is 1000 .mu.m ² or more 30000Myuemu ² or less The intermediate transfer method for electrophotography according to any one of (1) to (4) above, wherein the method is an intermediate transfer method for electrophotography.

(6): An electrophotographic image forming method comprising the electrophotographic intermediate transfer method according to any one of (1) to (5) above.

(7): An electrophotographic intermediate transfer system in which a metal soap is applied to an electrophotographic intermediate transfer belt containing nitrogen on the surface,
The content A (atm%) of nitrogen element obtained by measuring the surface of the intermediate transfer belt before applying the metal soap by XPS, and after applying the metal soap for 5 minutes in the absence of toner and paper The intermediate transfer belt exposure rate (B / A) × 100 (%) calculated from the nitrogen element content B (atm%) obtained by measuring the surface of the intermediate transfer belt with XPS is 30% or less. An intermediate transfer system for electrophotography, which is characterized by the following.

(8): The electrophotographic intermediate transfer system according to (7), wherein the metal soap is a mixture of zinc stearate and zinc palmitate.

(9): In the electrophotographic intermediate transfer system according to (8), the mixing ratio of the zinc stearate and the zinc palmitate is 73:27 to 45:55 weight ratio. is there.

(10): The intermediate transfer belt has a linear protrusion on the surface,
The intermediate transfer system for electrophotography according to any one of (7) to (9), wherein the convex portion has a height of 0.01 μm to 1 μm and a width of 0.5 μm to 5 μm. It is.

(11): the image forming region of the intermediate transfer belt is surrounded by a line-shaped convex portion, it is a plurality of small regions divided, and each area of the divided small regions is 1000 .mu.m ² or more 30000Myuemu ² or less The electrophotographic intermediate transfer system according to any one of (7) to (10) above, wherein

(12) An electrophotographic image forming apparatus comprising the electrophotographic intermediate transfer system according to any one of (7) to (11) above.

  According to the present invention, regardless of the structure of metal soap and the decomposition of metal soap, the state of coating of the metal soap on the intermediate transfer belt can be grasped, and the exposure rate on the surface of the intermediate transfer belt should be 30% or less. Thus, the effect of applying metal soap can be sufficiently obtained.

  According to the present invention, the metal soap is a mixture of zinc stearate and zinc palmitate, and the mixing ratio is 73:27 or more and 45:55 or less, so that the surface of the intermediate transfer belt is The coefficient of friction can be reduced more easily.

Furthermore, according to the present invention, there are linear convex portions having a height of 0.01 μm or more and 1 μm or less and a width of 0.5 μm or more and 5 μm or less on the surface of the intermediate transfer belt. When each area of the region surrounded by the part is 1000 μm ² or more and 30000 or less μm ² , it is possible to eliminate uneven application of the metal soap, which is a metal soap, and abnormalities such as voids, uneven density, and uneven color The image can be lost.

  Furthermore, according to the present invention, damage due to the pressure contact of the cleaning blade can be reduced, filming can be suppressed, electrical characteristics can be stabilized, wear resistance can be improved, the intermediate transfer belt can be extended in life, An intermediate transfer system for full-color electrophotography that provides high-quality full-color images that exhibit high transfer performance regardless of the surface properties of transfer media such as paper, and that do not have abnormal images such as voids, density unevenness, and color unevenness. be able to.

  According to the present invention, an electrophotographic intermediate transfer having a long life that forms a high-quality full-color image with stable electrical characteristics, excellent wear resistance, no abnormal images such as voids, uneven density, and uneven color. A method, an electrophotographic image forming method using the method, an electrophotographic intermediate transfer system, and an electrophotographic image forming apparatus using the same can be provided.

It is a graph showing transition of the exposure rate of the intermediate transfer belt surface with respect to the application time of the metal soap in the embodiment of the present invention. FIG. 3 is a schematic diagram of a main part of the image forming apparatus according to the present invention. FIG. 3 is a schematic view of a main part of a configuration example in which a plurality of photosensitive drums are arranged in parallel along a seamless belt in an image forming apparatus using an electrophotographic intermediate transfer system according to the present invention.

[Electrophotographic intermediate transfer method, electrophotographic intermediate transfer system]
The intermediate transfer method for electrophotography according to the present invention is an intermediate transfer method for electrophotography in which intermediate transfer is performed using an intermediate transfer belt for electrophotography containing nitrogen element on the surface, and the intermediate transfer belt for electrophotography is used as the intermediate transfer belt for electrophotography. A metal soap application step for applying metal soap, wherein the metal soap application step is a nitrogen element content A (atm%) obtained by measuring the surface of the intermediate transfer belt before application of the metal soap with XPS. And a nitrogen element content B (atm%) obtained by measuring the surface of the intermediate transfer belt with XPS after applying the metal soap for 5 minutes in the absence of toner and paper. The transfer belt exposure rate (B / A) × 100 (%) is 30% or less.
The intermediate transfer system for electrophotography according to the present invention is an intermediate transfer system for electrophotography in which metal soap is applied to an intermediate transfer belt for electrophotography containing nitrogen element on the surface, and the metal soap before application The content A (atm%) of nitrogen element obtained by measuring the surface of the intermediate transfer belt by XPS and the surface of the intermediate transfer belt after the metal soap is applied for 5 minutes in the absence of toner and paper. The content rate B (atm%) of the nitrogen element obtained by measurement in (1) above and the exposure rate (B / A) × 100 (%) of the intermediate transfer belt calculated from the above are 30% or less.

Next, the electrophotographic intermediate transfer method and the electrophotographic intermediate transfer system according to the present invention will be described in more detail.
Although the embodiments described below are preferred embodiments of the present invention, various technically preferable limitations are attached thereto, but the scope of the present invention is intended to limit the present invention in the following description. Unless otherwise described, the present invention is not limited to these embodiments.

<Electrophotographic intermediate transfer belt>
The electrophotographic intermediate transfer belt used in the present invention is preferably a seamless belt, but the present invention is not limited to this.
As a resin used for the seamless belt, a polyimide resin was used in terms of creep deformation and durability. As the polyimide resin, any of a thermoplastic type, a solvent-soluble type, and a thermosetting type can be used. Among these, in particular, a solution containing a polyimide precursor using an organic polar solvent (polyimide varnish) is applied in order to blend a necessity of blending various materials, particularly a resistance modifier for adjusting electrical resistance. A thermosetting type molded by thermosetting is preferred.

  In order to ensure an exposure rate of 30% or less on the surface of the intermediate transfer belt, it is very effective to moderately roughen the surface of the intermediate transfer belt. The methods include abrasives, polishing machines, blasting, pressing on rough molds, mechanical treatments such as changing the drying conditions, chemical treatments such as etching and electron beam treatment, filling with fillers, and roughing by spraying. Methods such as changing the prescription such as preparing the surface layer, extracting the solvent to be eluted, and extracting later are conceivable.

  Among these, as an optimum method, there is a method of producing a linear protrusion on the intermediate transfer belt. If there are convex portions on the intermediate transfer belt, the supply of metal soap is promoted around the convex portions. However, when the width of the convex portion is wide, the place where the supply of the metal soap is promoted is limited, and the supply amount of the metal soap is uneven. When the width of the convex portion is narrow and linear, the metal soap can be efficiently supplied to the intermediate transfer belt without unevenness.

<Production of linear protrusion>
A method for producing a linear convex portion on the intermediate transfer belt will be described below.
In order to produce the convex portion on the intermediate transfer belt, there are a method of producing a polyimide resin by thermosetting and molding, and a method of producing it on the surface of the intermediate transfer belt after molding.

  When forming a convex part when thermosetting a polyimide resin and forming, if it is a method of forming a film on a support, which is a general film forming method, a linear concave part is prepared on the surface of the support. Thus, a linear protrusion can be produced. Examples of film forming methods include centrifugal molding, roll coating, blade coating, ring coating, dipping, spray coating, dispenser coating, and die coating. Centrifugal molding is often used as a method for forming a polyimide seamless belt.

To produce a recess on the inner mold surfaces for centrifugal molding, that area of the small region surrounded by the concave portion is adjusted to 1000 .mu.m ² or more 30000Myuemu ² or less, within line-shaped convex portion of the surface of the intermediate transfer belt The controlled area can be controlled.

  As a method for producing the concave portion of the molding die, there are cutting, grinding, electrical machining, sputtering, and the like. In the present embodiment, the concave portion is formed by sputtering. Fine processing by cutting, grinding, and electrical processing is very expensive, and sputtering is preferably performed by sputtering because uniform processing on the outer circumference circle is possible and the cost is low.

  When producing a convex part on the surface of the intermediate transfer belt after the polyimide resin molding, as a production method, a method of pressing a thing with a concave part while heating using the thermoplasticity of the polyimide resin, a cutting process, a grinding process, There are electrical processing.

  The shape of the linear protrusions may be linear, but a combination of a gentle curve and a short straight line has a higher effect of uniformly attaching the metal soap than the straight shape. The linear protrusions can have various shapes such as lattice, honeycomb, and random. However, in the case of honeycomb or random, a large number of components that are oblique to the circumferential direction of the intermediate transfer belt are provided. However, since generation | occurrence | production of filming can be suppressed, compared with another shape, it is preferable.

The linear protrusion has a height of 0.01 μm to 1 μm, a width of 0.5 μm to 5 μm, more preferably a height of 0.02 μm to 0.1 μm, and a width of 1 μm to 2 μm. The area of the small region surrounded by the convex portion 1000 .mu.m ² or more 30000Myuemu ² or less, more preferably 3000 .mu.m ² or more 15000Myuemu ² or less.

  The linear protrusions are preferably the same height regardless of location, but the effect of the present invention is substantially maintained even if the height differs depending on the location or a part of it is slightly missing. The missing part is also regarded as having a convex part, and the area is calculated.

  If the height of the protrusion is less than 0.01 μm, the molecular length of zinc stearate, which is mainly used in metal soap, is about 0.01 μm, so the height is too low compared to the metal soap molecule itself. The metal soap cannot be supplied efficiently as in the flat case. If the height of the convex portion is larger than 1 μm, the convex portion itself becomes a foreign matter on the surface of the intermediate transfer belt, which causes an abnormal image. When the height is 0.02 μm or more and 0.1 μm or less, the effect of the convex portion is particularly sufficiently obtained and there is no possibility of causing an abnormal image as a foreign matter.

  If the width of the convex portion is less than 0.5 μm, the shape of the convex portion becomes too thin and the convex portion itself becomes fragile, and the convex portion may break and cause an abnormal image. If the width of the convex portion is larger than 5 μm, the shape is too gentle, and the metal soap cannot be supplied efficiently without changing from the flat case. When the width of the convex portion is 1 μm or more and 2 μm or less, the durability of the convex portion is particularly good, and the effect of the convex portion is sufficiently obtained.

When the area surrounded by the convex portions is less than 1000 μm ² , the surface glossiness of the intermediate transfer belt decreases due to an excessive supply amount of metal soap, and the density of the image formed on the intermediate transfer belt is measured. There is a possibility of affecting the so-called process control that adjusts the forming conditions, and that the metal soap itself may cause abnormal images as foreign matter. If the area surrounded by the convex portions is larger than 30000 μm ^2, the supply amount of the metal soap is too small in a situation where the linear transfer belt is fast, and this causes uneven application of the metal soap and causes an abnormal image.

  The height, width, and area surrounded by the protrusions are preferably constant, but sufficient protrusion effects can be obtained within the above range. The shape of the convex portion can be confirmed by a laser microscope, an optical interference microscope, an atomic force microscope (AFM), or a scanning electron microscope (SEM).

Moreover, the area surrounded by the convex part was calculated | required from the photograph of the scanning electron microscope. Based on the scale described in the photograph, a 400 × 400 μm region was enclosed, and each area of the region surrounded by the convex portion in the region was measured. By calculating the average of the measured areas, the area surrounded by the convex portions was obtained.
The area to be measured when calculating the area surrounded by the protrusions is selected depending on the density and shape of the protrusions, but is preferably 200 × 200 μm or more and 600 × 600 μm or less. If the area to be measured is less than 200 × 200 μm, local unevenness of the convex portion is greatly affected, and cannot be said to be a reliable numerical value. When the area to be measured is larger than 600 × 600 μm, since the field of view is too wide, it becomes difficult to measure the individual areas of the area surrounded by the convex portions, and it takes too much time.

  Next, the polyimide precursor which is a composition of the coating liquid used suitably for this invention and the polyimide produced | generated by the heat processing (imidation) of the said precursor are demonstrated in detail.

<Polyimide>
The polyimide used in the present invention is first obtained via a polyamic acid (polyimide precursor) by reaction of a generally known aromatic polycarboxylic acid anhydride or derivative thereof with an aromatic diamine. That is, polyimide is insoluble in solvents and the like due to its rigid main chain structure and has an infusible property. Therefore, a polyimide precursor that is soluble in an organic solvent from an acid anhydride and an aromatic diamine ( Polyamic acid or polyamic acid) is synthesized, and at this stage, molding is performed by various methods, and then the polyamic acid is subjected to dehydration reaction by heating or a chemical method to be cyclized (imidized) to obtain polyimide. The outline of the reaction is shown in the following chemical reaction formula (I).

In the chemical reaction formula (I), Ar ¹ represents a tetravalent aromatic residue containing at least one carbon 6-membered ring, and Ar ² represents a divalent aromatic residue containing at least one carbon 6-membered ring. Indicates.

  Specific examples of the aromatic polyvalent carboxylic acid anhydride include, for example, pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 2,2 ′, 3,3 '-Benzophenonetetracarboxylic dianhydride, 3,3', 4,4'-biphenyltetracarboxylic dianhydride, 2,2 ', 3,3'-biphenyltetracarboxylic dianhydride, 2,2- Bis (2,3-dicarboxyphenyl) propane dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, 2,2-bis ( 3, 4 Dicarboxylphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetra Carboxylic dianhydride, 1,2,5,6-naphthalene tetracarboxylic dianhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 3,4,9,10-perylene tetracarboxylic acid A dianhydride, 2,3,6,7-anthracene tetracarboxylic dianhydride, 1,2,7,8-phenanthrene tetracarboxylic dianhydride, etc. are mentioned. These may be used alone or in combination of two or more. In addition, other (non-aromatic) polyvalent carboxylic acid anhydrides such as ethylenetetracarboxylic dianhydride and cyclopentanetetracarboxylic dianhydride are included in a range not impairing the object of the present invention (50 mol%). Can be used in combination.

  Next, specific examples of the aromatic diamine to be reacted with the aromatic polycarboxylic acid anhydride include, for example, m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, m-aminobenzylamine, and p-aminobenzyl. Amine, 4,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, bis (3-aminophenyl) sulfide, (3-aminophenyl) (4-aminophenyl) sulfide, bis (4-aminophenyl) sulfide, bis (3-aminophenyl) sulfide, (3-aminophenyl) (4-aminophenyl) sulfoxide, bis (3-aminophenyl) sulfone, (3-aminophenyl) (4-amino Phenyl) sulfone, bis (4-aminophenyl) Ruhon, 3,3′-diaminobenzophenone, 3,4′-diaminobenzophenone, 4,4′-diaminobenzophenone, 3,3′-diaminodiphenylmethane, 3,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane, Bis [4- (3-aminophenoxy) phenyl] methane, bis [4- (4-aminophenoxy) phenyl] methane, 1,1-bis [4- (3-aminophenoxy) phenyl] ethane, 1,1- Bis [4- (4-aminophenoxy) phenyl] -ethane, 1,2-bis [4- (3-aminophenoxy) phenyl] ethane, 1,2-bis [4- (4-aminophenoxy) phenyl] ethane 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) ) Phenyl] propane, 2,2-bis [4- (3-aminophenoxy) phenyl] butane, 2,2-bis [3- (3-aminophenoxy) phenyl] -1,1,1,3,3 3-hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 1,3-bis (3-aminophenoxy) Benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 4,4′-bis (3- Aminophenoxy) biphenyl, 4,4′-bis (4-aminophenoxy) biphenyl, bis [4- (3-aminophenoxy) phenyl] ketone, bis [4- (4-aminophenoxy) phenyl] Ketone, bis [4- (3-aminophenoxy) phenyl] sulfide, bis [4- (4-aminophenoxy) phenyl] sulfide, bis [4- (3-aminophenoxy) phenyl] sulfoxide, bis [4- (4 -Aminophenoxy) phenyl] sulfoxide, bis [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] ether, Bis [4- (4-aminophenoxy) phenyl] ether, 1,4-bis [4- (3-aminophenoxy) benzoyl] benzene, 1,3-bis [4- (3-aminophenoxy) benzoyl] benzene, 4,4′-bis [3- (4-aminophenoxy) benzoyl] diphenyl ether, 4,4′- [3- (3-aminophenoxy) benzoyl] diphenyl ether, 4,4′-bis [4- (4-amino-α, α-dimethylbenzyl) phenoxy] benzophenone, 4,4′-bis [4- (4 -Amino-α, α-dimethylbenzyl) phenoxy] diphenylsulfone, bis [4- {4- (4-aminophenoxy) phenoxy} phenyl] sulfone, 1,4-bis [4- (4-aminophenoxy) phenoxy] -Α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-aminophenoxy) -α, α-dimethylbenzyl] benzene, and the like. These are used individually or in mixture of 2 or more types.

A polyimide precursor (polyamic acid) can be obtained by polymerizing the polycarboxylic acid anhydride component and the diamine component in an organic polar solvent using approximately equimolar amounts. Below, the manufacturing method of a polyamic acid is demonstrated concretely.
Examples of the organic polar solvent used in the polymerization reaction of polyamic acid include sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide, formamide solvents such as N, N-dimethylformamide and N, N-diethylformamide, N , N-dimethylacetamide, N, N-diethylacetamide and other acetamide solvents, N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone and other pyrrolidone solvents, phenol, o-, m-, or p- Phenolic solvents such as cresol, xylenol, halogenated phenol, catechol, ether solvents such as tetrahydrofuran, dioxane, dioxolane, alcohol solvents such as methanol, ethanol, butanol, cellosolve such as butyl cellosolve or hex Methyl phosphoramide, .gamma.-butyrolactone, etc. may be mentioned, it is desirable to use them alone or as a mixed solvent. The solvent is not particularly limited as long as it dissolves polyamic acid, but N, N-dimethylacetamide and N-methyl-2-pyrrolidone are particularly preferable.

As an example for producing a polyimide precursor, first, one or a plurality of diamines are dissolved in the above organic solvent or diffused in a slurry state in an inert gas atmosphere such as argon or nitrogen. When at least one polyvalent carboxylic acid anhydride or derivative thereof is added to this solution (either in a solid state, in a solution state dissolved in an organic solvent, or in a slurry state), it opens with heat generation. A cyclopolyaddition reaction occurs, and the viscosity of the solution is rapidly increased, and a high molecular weight polyamic acid solution is obtained. The reaction temperature at this time is preferably controlled to −20 ° C. to 100 ° C., desirably 60 ° C. or less. The reaction time is about 30 minutes to 12 hours.
The above is an example. Contrary to the addition procedure in the reaction, the polycarboxylic acid anhydride or derivative thereof may be first dissolved or diffused in an organic solvent, and the diamine may be added to the solution. . The diamine may be added in a solid state, in a solution state dissolved in an organic solvent, or in a slurry state. That is, the mixing order of the acid dianhydride component and the diamine component is not limited. Furthermore, the tetracarboxylic dianhydride and the diamine may be simultaneously added to the organic polar solvent and allowed to react.
As described above, the polyamic acid composition is uniformly mixed in the organic polar solvent by polymerizing the polycarboxylic acid anhydride or derivative thereof and the diamine component in an organic polar solvent in approximately equimolar amounts. A polyimide precursor solution is obtained in a dissolved state.

As the polyimide precursor solution (polyamic acid solution) in the present invention, the one synthesized as described above can be used, but the so-called polyamic acid composition is simply dissolved in an organic solvent. What is marketed as a polyimide varnish can also be obtained and used.
Typical examples include Trenice (manufactured by Toray Industries, Inc.), U-Varnish (manufactured by Ube Industries, Ltd.), Optmer (manufactured by JSR), SE812 (manufactured by Nissan Chemical Industries), CRC8000 (manufactured by Sumitomo Bakelite Co., Ltd.), and the like. It is mentioned as a thing.

  In addition, examples of the thermoplastic type include Aurum (Mitsui Chemicals) and Vespel (DuPont). Examples of the solvent-soluble type include Rika Coat (New Nippon Rika), block copolymerized polyimide (PI Engineering), GPI (Gunei Chemical Industry) and the like. These can be used by being added to and mixed with a thermosetting type material as a subcomponent resin within a range not impairing the object of the present invention.

  A coating liquid is prepared by blending a synthesized or obtained polyamic acid solution with a compound as necessary. The coating liquid is applied to a support (molding mold) and then subjected to a treatment such as heating, whereby conversion (imidation) from polyamic acid, which is a polyimide precursor, to polyimide is performed.

The method of converting from polyamic acid to polyimide can be imidized by a heating only method (1) or a chemical method (2). The heating-only method (1) is a method of converting polyamic acid to polyimide by heat treatment at 200 to 350 ° C., and is a simple and practical method for obtaining polyimide (polyimide resin). On the other hand, the chemical method (2) is a method in which a polyamic acid is reacted with a dehydrating cyclization reagent (such as a mixture of a carboxylic acid anhydride and a tertiary amine) and then subjected to a heat treatment to completely imidize. The method (1) is often used because it is a complicated and costly method compared to the heating-only method.
However, recently, although it is a kind of the above-mentioned method (2), a method of promoting imidization at the time of drying by incorporating an amine such as imidazole or quinoline as a catalyst in the varnish is often used. In order to demonstrate the intrinsic performance of polyimide, it is necessary to complete the imidization by heating above the glass transition temperature of the corresponding polyimide, but this promotes imidization at a lower temperature. It is said that mechanical durability is also improved. However, these catalysts are in very small amounts, and some of them decompose and sublime during drying, but some remain as impurities, which is not preferable.

The progress of imidization (degree of imidization) can be evaluated by a usual method for measuring the imidization rate.
As a method for measuring such an imidization rate, for example, nuclear magnetic resonance spectroscopy calculated from an integration ratio of 1H attributed to an amide group in the vicinity of 9 to 11 ppm and 1H attributed to an aromatic ring in the vicinity of 6 to 9 ppm. Various methods are used such as a method (NMR method), Fourier transform infrared spectroscopy (FT-IR method), a method for quantifying moisture accompanying imide ring closure, and a carboxylic acid neutralization titration method. Outer spectroscopy (FT-IR method) is the most common method.

  In Fourier transform infrared spectroscopy (FT-IR method), the imidization rate is defined as follows, for example. That is, assuming that (A) is the number of moles of imide groups at the firing stage (imidation treatment stage) and (B) is the number of moles of imide groups when 100% imidized (theoretical), It is.

  Imidation ratio = [(A) / (B)] × 100

  The number of moles of the imide group in this definition can be determined from the absorbance ratio of the characteristic absorption of the imide group measured by the FT-IR method. For example, as a typical characteristic absorption, the imidization ratio can be evaluated using the following absorbance ratio.

(1) Absorbance ratio between 725 cm ⁻¹ (immobilization vibration band of imide ring C═O group), which is one of characteristic absorptions of imide, and 1,015 cm ⁻¹ of characteristic absorption of benzene ring (2) Characteristics of imide Absorbance ratio between 1,380 cm ⁻¹ (inflection band of imide ring C—N group) which is one of absorption and characteristic absorption 1,500 cm ^{−1 of} benzene ring (3) One of characteristic absorption of imide Absorbance ratio between 1,720 cm ⁻¹ (an oscillating band of imide ring C═O group) and 1,500 cm ⁻¹ characteristic absorption of benzene ring (4) 1, which is one of characteristic absorption of imide Absorbance ratio between 720 cm ⁻¹ and amide group characteristic absorption 1,670 cm ⁻¹ (interaction between amide group N—H bending vibration and C—N stretching vibration)

Moreover, if it is confirmed that the multiple absorption band derived from the amide group over 3000 to 3300 cm ⁻¹ disappears, the reliability of imidization completion is further increased.

In the coating solution suitably used in the present invention, another resin may be used in combination with the polyimide. In addition, various materials for imparting necessary functions as an intermediate transfer belt are blended.
As a material to be blended, for example, a resistance adjusting agent, a reinforcing material, a leveling agent, a surfactant, a lubricant, an antioxidant, a catalyst, and the like can be blended. Of these, the resistance adjusting agent is particularly important.

Next, the resistance adjuster will be described. The resistance adjuster is indispensable for adjusting the intermediate transfer belt to a predetermined resistance value.
Any resistance adjusting agent can be used as long as it can adjust the resistance value of polyimide. For example, carbon black, graphite, or metals such as copper, tin, aluminum, indium, tin oxide, zinc oxide, titanium oxide, indium oxide, antimony oxide, bismuth oxide, tin oxide doped with antimony, tin doped Fillers such as metal oxide fine powders such as indium oxide, conductive polymer materials such as polyetheramide, polyetheresteramide, polypyrrole, polythiophene, polyaniline, tetraalkylammonium salt, trialkylbenzyl, ammonium Salt, alkyl sulfonate, alkyl benzene sulfonate, alkyl sulfate, glycerol fatty acid ester, sorbitan fatty acid ester, polyoxyethylene alkylamine, polyoxyethylene fatty alcohol ester, alkyl Tyne, may be used an ion-conductive material, such as lithium perchlorate. These can also be used in combination. In addition, the resistance adjusting agent in the present invention is not limited to these exemplary compounds.

In the present invention, carbon black is preferably used among the resistance adjusting agents.
As the carbon black, furnace black, acetylene black, ketjen black, channel black, and the like can be used. Oxidized carbon black obtained by oxidizing these surfaces is preferable.
Moreover, you may use a dispersing aid as needed. Furthermore, the surface functional group of carbon black and an organic compound having reactivity with the functional group may be surface-treated.

Next, a method for producing a seamless belt using the coating liquid containing the polyimide precursor will be described. For example, it is manufactured by the following process.
A dispersion preparing step for dispersing a resistance adjusting agent in a polyamic acid solution, a coating solution preparing step for adjusting the dispersion obtained by the step to the content of a predetermined resistance adjusting material, and a coating solution prepared by the step The step of applying and casting to (molding mold), the step of removing the solvent in the coating applied and cast on the support by heating, the precursor imide contained in the coating by heating at elevated temperature It is manufactured by releasing the formed thin film from the support and making it a seamless belt.

In the step of dispersing the resistance adjusting agent, there are a method of dispersing and mixing the resistance control agent directly in the polyimide precursor solution or a method of dispersing the resistance control agent in a solvent in advance and then mixing with the polyimide precursor solution.
Here, a method of dispersing carbon black as a resistance control agent will be described as an example. Note that this is an example and the present invention is not limited to this.

N-methyl-2-pyrrolidone is mixed with a small amount of carbon black and a polyimide precursor, and dispersed in a ball mill, paint shaker, bead mill or the like for a predetermined time using zirconia beads. After being dispersed to a certain particle size, the liquid taken out is used as a dispersion.
The polyimide precursor solution is mixed with the dispersion to dilute to a predetermined carbon black concentration. As a mixing method at this time, a centrifugal stirrer, a Henschel mixer, a homogenizer, a planetary stirrer, or the like can be used.
If necessary, additives such as a leveling agent and a catalyst can be added at this time.
Further, after stirring, it is preferable to defoam using a vacuum defoamer or the like.

Next, the process of curing the coating film produced by the above process will be described.
As described in the method for producing linear protrusions on the intermediate transfer belt, after forming recesses by sputtering on the outer surface of a metal cylindrical support that is a mold for centrifugal molding, a mold release agent is applied to the mold. And after apply | coating the coating liquid containing the polyamic acid of a predetermined film thickness, a coating film is dried with a hot air dryer, IH heater, a far-infrared heater, etc. In drying, first, drying is performed at a temperature of about 80 to 120 ° C. for 10 to 60 minutes, and then the temperature is increased at a temperature rising rate of about 2 to 5 ° C./min, and imidization baking is performed at 300 to 400 ° C. Do.

The film thickness of the intermediate transfer belt formed in the present invention is preferably 50 μm or more and 100 μm or less. If the film thickness is too thin, the strength is insufficient and the durability is inferior. If it is too thick, the rigidity is too large to be stably driven by a driving roller having a small curvature.
Moreover, as content of carbon black as a resistance regulator, 5 wt% or more and 25 wt% or less are preferable. If the carbon black content is too small (less than 5 wt%), it is difficult to control the variation of the resistance value, and if it is too large (over 25 wt%), the film is brittle and has poor flexibility and poor durability.
Further, the volume resistance value of the intermediate transfer belt is preferably 10 ⁶ Ωcm or more and 10 ¹⁰ Ωcm or less. If the resistance value is too low (less than 10 ⁶ Ωcm), the toner is scattered in the non-image area during transfer and the sharpness is lowered. On the other hand, if it is too high (over 10 ¹⁰ Ωcm), the transfer electric field does not work well, which is not preferable in terms of transfer efficiency.

<Metal soap>
Next, the metal soap which is a lubricant used in the present invention will be described.
As the metal soap, those having a stearic acid group such as zinc stearate, barium stearate, iron stearate, nickel stearate, cobalt stearate, copper stearate, strontium stearate and calcium stearate can be used. .
Also, the same fatty acid groups zinc oleate, barium oleate, lead oleate, zinc oleate, barium oleate, iron oleate, nickel oleate, cobalt oleate, copper oleate, strontium oleate, olein Those having an oleic acid group such as calcium acid can be used.
In addition, use those having a palmitic acid group such as zinc palmitate, barium palmitate, lead palmitate, iron palmitate, nickel palmitate, cobalt palmitate, copper palmitate, strontium palmitate, calcium palmitate, etc. Can do.
Those listed above are likely to be organic solid metal soaps and have good compatibility with toners.
In addition, the metal soap used by this invention does not contain a nitrogen element. However, nitrogen elements may be contained as long as they are contained as impurities.

<Zinc stearate and zinc palmitate>
In the present invention, it is preferable to use a mixture of zinc stearate and zinc palmitate as the metal soap. Mixing a certain amount of zinc palmitate and zinc stearate is preferable because even if the linear transfer speed of the intermediate transfer belt is high, the metal soap is stretched on the intermediate transfer belt and can sufficiently cover the intermediate transfer belt. .

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. Therefore, zinc stearate and zinc palmitate are similar in structure, are well compatible and behave as substantially the same material, both of which can protect the intermediate transfer belt in the same way.
In addition, although details are not clear, zinc palmitate has a lower melting point than zinc stearate, so if a certain amount or more of zinc palmitate is contained, the metal soap tends to be stretched, so intermediate transfer It is presumed that even if the belt linear velocity is high, the metal soap can sufficiently cover the intermediate transfer belt.

  In addition, as the linear velocity of the photosensitive member increases, the charging energy poured onto the intermediate transfer belt, particularly the AC charging energy, becomes stronger. Therefore, in order to enhance the protection effect of the intermediate transfer belt by metal soap, It is necessary to increase the thickness of the metal soap.

Zinc stearate is not attached randomly on the intermediate transfer belt, but is stable when attached with two molecules. That is, even if zinc stearate is applied on the intermediate transfer belt, it is saturated at the thickness of two molecules of zinc stearate.
Here, when a certain amount of zinc palmitate having a slightly shorter molecular length than zinc stearate is contained, the height of the molecular layer is not constant, and the lower part and the higher part coexist. . Then, the next molecule enters the lower part and forms a molecular layer. Therefore, as a result, a metal soap layer thicker than two molecules can be formed, and it is assumed that the protective effect of the intermediate transfer belt is improved. Naturally, when the amount of zinc palmitate becomes too large, a zinc palmitate bimolecular layer is likely to be formed, and the thickness of the metal soap does not increase. In addition, since zinc palmitate has a smaller molecule than zinc stearate, the protective effect of the intermediate transfer belt is reduced compared to zinc stearate alone.

  The weight ratio of zinc stearate and zinc palmitate in the metal soap used in the present invention is preferably 73:27 or more and 45:55 or less. This weight ratio is preferable because the metal soap protects the entire intermediate transfer belt even when the linear speed of the intermediate transfer belt is high, the thickness of the metal soap layer is not reduced, and the protective effect of the metal soap is enhanced.

The metal soap used in the present invention may contain a different metal soap in addition to zinc stearate and zinc palmitate. However, a metal soap structurally different from zinc stearate and zinc palmitate is not preferable because zinc stearate and zinc palmitate may disturb the metal soap layer formed on the intermediate transfer belt. A metal soap having a structure similar to that of zinc palmitate (a fatty acid zinc soap having 13 to 20 carbon atoms) is preferred.
In the following, a metal soap composed of zinc stearate and zinc palmitate will be described by way of example, but the present invention is not limited to this.

  In the present invention, the metal soap powder may be supplied directly onto the intermediate transfer belt. However, the metal soap is processed into a block shape, and a brush or the like is rubbed against the metal soap block to finely pulverize the metal soap. It is preferable to supply the transfer belt to the transfer belt because the metal soap can be easily stored and the metal soap application means is simple, and a uniform metal soap can be supplied.

When the metal soap block is prepared by melt molding, the metal soap block can be prepared by melting and mixing zinc stearate and zinc palmitate, pouring the molten metal soap into a mold, and cooling. .
The produced metal soap block is used by being affixed to a base material such as metal, alloy or plastic with an adhesive or the like.

  In the present invention, the ratio of zinc stearate and zinc palmitate in the metal soap block may be calculated by the amount of material input if the material to be used is surely known, but the material always contains impurities. Therefore, it is preferable to measure the ratio of zinc stearate and zinc palmitate in the manufactured metal soap block for each production lot. The ratio of zinc stearate and zinc palmitate in the metal soap block was determined by dissolving the metal soap block in hydrochloric acid-methanol solution and heating at 80 ° C., methylating stearic acid and palmitic acid, and gas chromatography. The ratio of stearic acid and palmitic acid can be determined, and the ratio can be calculated by converting it to the ratio of zinc stearate and zinc palmitate.

<Calculation of intermediate transfer belt surface exposure rate>
Next, a method of calculating the intermediate transfer belt surface exposure rate after applying metal soap in the present invention for 5 minutes in the absence of toner and paper will be described.
As a method of applying metal soap in the absence of toner and paper, the image forming apparatus can perform image forming operation without inputting toner and paper, or the same intermediate transfer unit as that using the image forming apparatus can be used as a toner. In addition, a method of operating in a state where no paper is input can be exemplified, but in the present invention, either method may be used.
FIG. 1 is a graph showing the transition of the intermediate transfer belt surface exposure rate with respect to the application time of the metal soap in the embodiment of the present invention. Metal soap is rapidly accumulated on the intermediate transfer belt after the start of application, and after a few minutes, the accumulated amount is almost saturated and stabilized. In this embodiment, the accumulated amount of metal soap is stabilized, and as the time until the accumulated amount is stabilized so that the reproducibility of the measurement data can be obtained, data for 5 minutes after starting application of the metal soap with a margin is taken. It was decided. According to the embodiment of the present invention, in various image forming apparatuses, the time until the accumulated amount of metal soap is stabilized is less than 5 minutes.

  When obtaining data on the state of application of metal soap, the detection depth of the analytical instrument becomes very important. That is, if the analysis depth is too deep, if the metal soap is thinly coated on the intermediate transfer belt, only the signal of the intermediate transfer belt may be detected strongly. XPS (X-ray Photoelectron Spectroscopy) detects only the depth of 5 to 8 nm on the extreme surface, and is therefore very preferable as a method for analyzing the state of metal soap thinly coated on an intermediate transfer belt.

  The intermediate transfer belt surface exposure rate is 5 minutes in the absence of toner and paper with a nitrogen element content Aatm% and metal soap obtained by measuring the (initial) intermediate transfer belt surface before image formation by XPS. The intermediate transfer belt surface after coating is calculated from the nitrogen element content Batm% obtained by measuring with XPS. In the present invention, there is no metal soap containing nitrogen element, and the reduction rate of the nitrogen element can be regarded as the reduction rate of the exposure rate on the surface of the intermediate transfer belt. Therefore, the exposure rate on the surface of the intermediate transfer belt can be calculated by (A / B) × 100 (%).

  The coverage of the metal soap on the surface of the intermediate transfer belt can be considered as 100− (exposure rate on the surface of the intermediate transfer belt). For this reason, the smaller the exposure rate of the surface of the intermediate transfer belt, the better. More preferably, it is 20% or less, and further preferably 10% or less.

<Zinc element content on intermediate transfer belt surface>
Furthermore, by confirming the content of zinc element on the surface of the intermediate transfer belt after applying the metal soap for 5 minutes in the absence of toner and paper, it is confirmed that the deposit on the intermediate transfer belt is metal soap. You can also.
The content of zinc element on the surface of the intermediate transfer belt is obtained from XPS measurement on the surface of the intermediate transfer belt after applying metal soap for 5 minutes in the absence of toner and paper. The zinc element content is preferably 1.7 atm% or more and 2.5 or less atm%. If the zinc element content is less than 1.7%, even if the surface coverage is 70% or more, the surface deposit may be a substance other than metal soap, and the metal soap is applied to the surface sufficiently. It is not preferable because it cannot be confirmed. If the zinc element content is higher than 2.5%, the metal soap itself may be decomposed because the concentration of zinc is too high even if the metal soap covers 100% of the surface. This is not preferable because it is not possible to confirm that the soap has been successfully applied to the surface of the intermediate transfer belt.

[Image forming apparatus and image forming method]
Next, an embodiment of the image forming apparatus according to the present invention will be described.
In the present embodiment, an image forming apparatus using an electrophotographic intermediate transfer system including the above-described seamless belt will be described in detail below with reference to a schematic diagram of a main part around the seamless belt. The schematic diagram is an example, and the present invention is not limited to this.
Also, in an image forming apparatus using an electrophotographic intermediate transfer system in which metal soap is applied onto a seamless belt, the toner and paper are not supplied, and otherwise the metal soap is used in the same manner as in normal image formation. Application may be performed for 5 minutes in the absence of toner and paper. In addition, after applying metal soap for 5 minutes, toner and paper are supplied, and normal image formation is performed.

The schematic diagram of FIG. 2 shows a schematic configuration of a main part of an image forming apparatus using an electrophotographic intermediate transfer system.
The intermediate transfer unit (500) that is the belt component shown in FIG. 2 includes an intermediate transfer belt (501) that is an intermediate transfer member stretched around a plurality of rollers. Around the intermediate transfer belt (501), there are a secondary transfer bias roller (605) as a secondary transfer charge applying means of the secondary transfer unit (600), and a belt cleaning blade (504) as an intermediate transfer body cleaning means. A metal soap application brush (505), which is a metal soap application member of the metal soap application means, is disposed so as to face each other.

  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), which are primary transfer charge applying means, and a cleaning device. It is stretched between the counter roller (511) and the feedback current detection roller (512). Each roller is made of a conductive material, and each roller other than the primary transfer bias roller (507) is grounded. The primary transfer bias roller (507) is controlled by a primary transfer power source (801) controlled by a constant current or a constant voltage so that the current or voltage is controlled to a predetermined magnitude according to the number of superimposed toner images. A bias is applied.

  The intermediate transfer belt (501) is driven in the direction of the arrow by a belt drive roller (508) that is driven to rotate in the direction of the arrow by a drive motor (not shown). The intermediate transfer belt (501), which is the belt component, is usually a semiconductor or an insulator and has a single-layer or multi-layer structure, but the above-mentioned seamless belt is preferably used, thereby improving durability. At the same time, excellent image formation can be realized. In addition, the intermediate transfer belt is set to be larger than the maximum sheet passing size in order to superimpose the toner images formed on the photosensitive drum (200).

  A secondary transfer bias roller (605), which is a secondary transfer means, is in contact with / separating means, which will be described later, with respect to the belt outer peripheral surface of a portion of the intermediate transfer belt (501) stretched around the secondary transfer counter roller (510). It is comprised so that contact / separation is possible by the contact / separation mechanism. 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). A transfer bias having a predetermined current is applied by a secondary transfer power source (802) controlled at a constant current.

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

  In the color copying machine having such a configuration, when the image forming cycle is started, the photosensitive drum (200) is rotated in the counterclockwise direction indicated by an arrow by a drive motor (not shown), and a charging charger is used according to each color. After charging by (203) and image exposure by light (L) from an exposure means (not shown), Bk (black) toner image formation, C (cyan) toner image formation, M on the photosensitive drum (200) (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, 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. 2, 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 charged uniformly, 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 adheres to the portion where the charge of the photosensitive drum (200) remains. In other words, toner is attracted to a portion having no charge, that is, an 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 way is primary on the belt outer peripheral surface of the intermediate transfer belt (501) rotating at a constant speed while being in contact with the photosensitive drum (200). Transcribed. 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). Is done. On the photosensitive drum (200) side, the process proceeds to the Y image forming process after the Bk image forming process, and reading of Y image data by a color scanner starts at a predetermined timing. A Y electrostatic latent image is formed on the surface of the body drum (200).

Then, after the rear end portion of the previous Bk electrostatic latent image passes and before the front end portion of the electrostatic latent image reaches, the revolver developing unit (230) is rotated, and the Y developing machine (231Y ) Is set at the development position, and the Y electrostatic latent image is developed with Y toner. Thereafter, the development of the Y electrostatic latent image area is continued, but when the rear end of the Y electrostatic latent image passes, the revolver developing unit is rotated in the same manner as in the previous Bk developing machine (231K). Then, the next C developing machine (231C) is moved to the developing position. This is also completed before the leading edge of the next C electrostatic latent image reaches the developing position. Note that the C and M image forming steps are the same as the Bk and Y steps described above because the color image data reading, electrostatic latent image forming, and developing operations are the same as those described above.
In addition to the above, there are a potential sensor 204 for detecting the electric potential of the photoconductor 200 and detecting the charged state before exposure and before development, as shown in FIG. In addition, it is preferable to arrange a toner image density sensor 205 for detecting the image density on the photoreceptor 200 before transfer.

  The Bk, Y, C, and M 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 (513) 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).

  Then, on the intermediate transfer belt (501), the intermediate transfer belt (501) stretched around the secondary transfer counter roller (510) and the secondary transfer bias roller (605) form a nip. When the leading edge of the toner image approaches, 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 is transferred along the transfer paper guide plate (601). The paper (P) is conveyed and registration of the transfer paper (P) and the toner image is performed.

  This transfer paper (P) is conveyed along the transfer paper guide plate (601) and passes through a portion facing the transfer paper neutralization charger (606) comprising a static elimination needle disposed downstream of the secondary transfer portion. After being neutralized by this, the belt is conveyed toward the fixing device (270) by the belt conveying device (210) which is a belt component (see FIG. 2). Then, after the toner image is melted and fixed at the nip portion 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). Stacked face up on a copy tray (not shown). 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). The 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 contact and separate at a predetermined timing with respect to the belt outer peripheral surface of the intermediate transfer belt (501) by a cleaning member separating and contacting mechanism (not shown).

  A toner seal member (503) that contacts and separates from the belt outer peripheral surface of the intermediate transfer belt (501) is provided on the upstream side of the belt cleaning blade (504) in the moving direction of the intermediate transfer belt (501). Yes. The toner seal member (503) receives the falling toner dropped from the belt cleaning blade (504) during cleaning of the residual toner, and the falling toner is scattered on the transfer path of the transfer paper (P). It is preventing. The toner seal member (503) 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 metal soap (506) scraped by the metal soap 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 manner. The metal soap (506) is disposed in contact with the metal soap 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) in contact with the outer peripheral surface of the intermediate transfer belt (501). Here, the metal soap 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). It has become.

  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 image formation process for the fourth color (M) of the first sheet. The process proceeds to the image forming process for the first color (Bk). The intermediate transfer belt (501) has two sheets 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 Bk toner image of the eye is primarily 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 number of times. In the case of the single color copy mode, only the developing device of the predetermined color 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 moved to the intermediate transfer belt (501). The copy operation is performed with the touch panel kept in contact.

In addition, an optical sensor (514) disposed to face the surface of the intermediate transfer belt (501) may be provided. The optical sensor (514) has a primary transfer position (a position where the photosensitive member 200 and the primary transfer bias roller 507 face each other) and a secondary transfer position (the secondary transfer bias roller 605 and the secondary transfer counter roller 510 which face each other). Position), and the amount of adhesion and the belt running position are detected by detecting a predetermined sample image that has been primarily transferred.
Furthermore, a neutralizing roller (70) disposed in contact with the back surface of the intermediate transfer belt (501) and an earth roller (80) may be provided. The neutralization roller (70) is a conductive roller and neutralizes residual charges on the intermediate transfer belt (501). The earth roller (80) is a metal roller and makes the potential after neutralization by the neutralization roller (70) of the intermediate transfer belt (501) zero. Accordingly, the residual potential of the intermediate transfer belt (501) can be prevented from affecting the next image formation.

In the above embodiment, the copying machine including only one photosensitive drum 200 has been described. However, the image forming apparatus according to the present invention includes, for example, a plurality of photosensitive drums as shown in FIG. The present invention can also be applied to an image forming apparatus arranged along the line.
FIG. 3 shows four drums including four photosensitive drums (21BK), (21Y), (21M), and (21C) for forming toner images of four different colors (black, yellow, magenta, and cyan). 1 shows an example of the configuration of a type digital color printer.

  In FIG. 3, a printer main body (10) performs exposure (12) from an image writing unit (not shown), an image forming unit (13), a paper feeding unit (14), for performing color image formation by electrophotography. It is composed of Based on the image signal, the image processing unit converts the image signal into black (BK), magenta (M), yellow (Y), and cyan (C) color signals for image formation, and the image writing unit (12). Send to. 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, and corresponds to each color signal described above. An image document corresponding to each color signal is provided in an image carrier (photosensitive member) (21BK), (21M), (21Y), and (21C) having four writing optical paths and provided for each color of the image forming unit. Do the following.

  The image forming unit (13) is a photoconductor (21BK), (21M), (21Y) which is an image carrier for black (BK), magenta (M), yellow (Y), and cyan (C). ), (21C). As each photoconductor for each color, an OPC photoconductor is usually used. Around each of the photoconductors (21BK), (21M), (21Y), and (21C), a charging device, an exposure unit irradiated with laser light (12) from the image writing unit, black, magenta, and yellow , Cyan developing devices (20BK), (20M), (20Y), (20C) primary transfer bias rollers (23BK), (23M), (23Y), (23C) as primary transfer means , A cleaning device (not shown), a photosensitive member static elimination device (not shown), and the like are provided. 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, includes the photosensitive members (21BK), (21M), (21Y), and (21C) and the primary transfer bias rollers (23BK), (23M), and (23Y). , (23C), and the toner images of the respective colors formed on the respective photoreceptors are sequentially superimposed and transferred. The intermediate transfer belt (22) is stretched around a belt driving roller (24) and a belt driven roller (26).

  On the other hand, the transfer paper (P) is fed from the paper feed section (14) and then carried by the transfer conveyance belt (50), which is a belt constituting section, via the registration rollers (16). When the intermediate transfer belt (22) and the transfer conveying belt (50) come into contact with each other, the toner image transferred onto the intermediate transfer belt (22) is transferred to a secondary transfer bias roller (60) as a secondary transfer unit. ) For secondary transfer (collective transfer). Thereby, 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). After the image transferred by the fixing device (15) is fixed, the transfer paper (P) is removed from the printer main body. To be discharged.

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 device (25). It is preferable to provide a neutralization means (27) upstream of the belt cleaning device (25) in the belt rotation direction to neutralize the secondary transfer residual toner. On the other hand, a metal soap applicator (not shown) is disposed on the downstream side of the belt cleaning device (25). This metal soap applicator comprises a solid metal soap and a conductive brush that rubs the intermediate transfer belt (22) to apply the solid metal soap. The conductive brush is always in contact with the intermediate transfer belt (22), and solid metal soap is applied to the intermediate transfer belt (22).
In addition, an optical sensor (28) arranged to face the surface of the intermediate transfer belt (22) may be provided. The optical sensor (28) includes a primary transfer position (a position where the photoconductor 21 and the primary transfer bias roller 23 face each other) and a secondary transfer position (a position where the secondary transfer bias roller 60 and the intermediate transfer belt 22 face each other). By detecting a predetermined sample image that has been primarily transferred, the amount of adhesion and the belt running position are detected.
Further, a bias roller (70) arranged in contact with the back surface of the intermediate transfer belt (22) may be provided. The bias roller (70) is a conductive roller, and by applying a bias to the intermediate transfer belt (22), the burden on the primary transfer bias roller (23) can be reduced.

  The above-described seamless belt can be suitably applied to an intermediate transfer belt type image forming apparatus equipped with the above-described intermediate transfer belt (501) or (22), and the intermediate transfer belt (501) or (22). The image forming apparatus can also be applied to a transfer conveyance belt type image forming apparatus equipped with a transfer conveyance belt. Further, in the case of an image forming apparatus using a transfer / conveying belt system, the present invention can be applied to either the 1-photosensitive drum system or the 4-photosensitive drum system.

  Further, the linear speed of the intermediate transfer belt may be any speed, but is preferably 200 mm / sec or more. When the linear speed of the intermediate transfer belt is 450 mm / sec or more, uneven application of the metal soap occurs unless the embodiment of the present invention is used.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by these examples without departing from the gist thereof.

(XPS analysis conditions)
The XPS analysis was performed with AXIS / ULTRA, Shimadzu / KRATOS, X-ray source: Mono Al, analysis area: 700 × 300 μm.

○ Example 1
[Preparation of Intermediate Transfer Belt A]
First, the following constituent materials were mixed and dispersed using a zirconia bead of φ1 mm for 5 hours with a bead mill disperser to prepare a carbon dispersion.

<Dispersion composition material>
・ Polyimide solution U-Varnish A (Ube Industries, solid content 18% by weight) 2 parts ・ Carbon black Specialblack 4A (Degussa) 8 parts ・ N-methyl-2-pyrrolidone (Mitsubishi Chemical) 90 parts by weight

  Using the above dispersion, the following constituent materials were mixed, mixed and defoamed with a centrifugal stirring deaerator to obtain a coating solution.

<Coating liquid composition material for base layer>
-50 parts by weight of the above carbon black dispersion-50 parts by weight of polyimide solution U-varnish A (manufactured by Ube Industries; solid content 18 wt%)-0.01 parts by weight of polyether-modified silicon FZ2105 (manufactured by Toray Dow Corning)

<Preparation of seamless belt>
Next, a drum-shaped metal cylinder having an outer diameter of 100 mm and a length of 300 mm with a release agent applied to the inner wall is used as a mold, and the coating liquid is applied to the metal cylinder while rotating the metal cylinder at 50 rpm (times / minute). The inner surface was uniformly poured and applied. A linear recess having a height of 0.01 μm and a width of 1 μm was formed on the inner surface of the drum-shaped metal cylinder by sputtering, and the area surrounded by the recess was adjusted to 3000 μm ² . The coating amount was such that the final film thickness was 70 μm. When the predetermined amount was completely poured and the coating film was spread evenly, it was put into a hot air circulating dryer while rotating, heated to 100 ° C. at a heating rate of 3 ° C./min, and heated for 30 minutes. Thereafter, the rotation was stopped, the mixture was put into a heating furnace (baking furnace) capable of high temperature treatment, heated to 310 ° C. at a heating rate of 2 ° C./min, and subjected to heat treatment (baking) for 60 minutes. After stopping the heating, it was gradually cooled to room temperature.
As a result, an intermediate transfer belt A in which linear convex portions having a height of 0.01 μm and a width of 1 μm exist on the surface and the area surrounded by the convex portions is 3000 μm ² was obtained.

[Preparation of metal soap A]
Zinc stearate and zinc palmitate (primary particle size: 0.18 μm) are weighed to the following ratios, heated to 145 ° C. to melt, poured molten metal soap into the mold and cooled. Thus, a metal soap block having a size of 40 mm × 8 mm × length 350 mm was produced (because it is produced by melt molding, the degree of compression is 100%). This lubricating block was attached to a base material for metal soap with an adhesive to obtain metal soap A.

<Metal soap constituent materials>
・ Zinc stearate 45 weight ratio ・ Zinc palmitate 55 weight ratio

<Evaluation method>
The surface of the obtained intermediate transfer belt A was measured by XPS to obtain a nitrogen element content. Thereafter, the intermediate transfer belt A and the metal soap A are installed in the image forming apparatus shown in FIG. 2, and toner and paper are not supplied, and the intermediate transfer belt A is coated with metal soap for 5 minutes as an electrophotographic intermediate transfer system. Was made. The metal soap is urged to the brush at 20 gf / cm, and the brush is rotated to pulverize the metal soap, supplied to the intermediate transfer belt A, and stretched and applied by the blade.
Thereafter, the intermediate transfer belt A coated with metal soap was taken out, and the surface of the intermediate transfer belt A was measured by XPS to obtain nitrogen element and zinc element contents. The exposure rate on the surface of the intermediate transfer belt A was calculated from the nitrogen element content reduction rate.

Thereafter, the intermediate transfer belt A was again incorporated into a normal image forming apparatus (FIG. 2) to which toner and paper were supplied, and a test chart having an image density of 7% was formed on 1000 sheets in an environment of 23 ° C. and 45%. . The paper used was TYPE 6200 (Ricoh). The linear speed of image formation was 250 mm / second. At the same time, each image output under the above conditions was evaluated.
Next, when no abnormal image was found in the above evaluation, the image forming linear velocity was increased to 450 mm / second, and a test chart with an image density of 7% was printed at 5% in an environment of 23 ° C. and 45%. A total of 30,000 images were formed one by one, and each output image was evaluated.

Example 2
[Preparation of Intermediate Transfer Belt B]
It was produced by the same method except for the intermediate transfer belt A described in Example 1 and the shape of the convex portion on the surface. Height 0.02μm to mold the inner surface, to produce a linear recess width 1 [mu] m, the area surrounded by the recess is adjusted to 3000 .mu.m ^2, height 0.02μm on the surface, the width of 1 [mu] m An intermediate transfer belt B having linear convex portions and an area surrounded by the convex portions being 3000 μm ² was obtained.
The metal soap A described in Example 1 was used as the metal soap, and the evaluation method was the same as that of Example 1 except that the intermediate transfer belt B was used instead of the intermediate transfer belt A described in Example 1.

Example 3
[Preparation of Intermediate Transfer Belt C]
It was produced by the same method except for the intermediate transfer belt A described in Example 1 and the shape of the convex portion on the surface. Height 0.1 [mu] m in mold inner surface, to produce a linear recess width 1 [mu] m, the area surrounded by the recess is adjusted to 3000 .mu.m ^2, the height on the surface 0.1 [mu] m, a width of 1 [mu] m An intermediate transfer belt C having linear convex portions and having an area surrounded by the convex portions of 3000 μm ² was obtained.
The metal soap A described in Example 1 was used as the metal soap, and the evaluation method was the same as in Example 1 except that the intermediate transfer belt C was used instead of the intermediate transfer belt A described in Example 1.

Example 4
[Preparation of Intermediate Transfer Belt D]
It was produced by the same method except for the intermediate transfer belt A described in Example 1 and the shape of the convex portion on the surface. Height 1 [mu] m in mold inner surface, to produce a linear recess width 1 [mu] m, the area surrounded by the recess is adjusted to 3000 .mu.m ^2, the height on the surface height 1 [mu] m, like line width 1 [mu] m The intermediate transfer belt D having an area of 3000 μm ² was obtained.
The metal soap A described in Example 1 was used as the metal soap, and the evaluation method was the same as that of Example 1 except that the intermediate transfer belt D was used instead of the intermediate transfer belt A described in Example 1.

Example 5
[Preparation of Intermediate Transfer Belt E]
It was produced by the same method except for the intermediate transfer belt A described in Example 1 and the shape of the convex portion on the surface. Height 0.1μm to mold the inner surface, to produce a linear recess width 0.5 [mu] m, the area surrounded by the recess is adjusted to 3000 .mu.m ^2, height Height 0.1μm on the surface An intermediate transfer belt E having linear convex portions with a width of 0.5 μm and an area surrounded by the convex portions of 3000 μm ² was obtained.
The metal soap A described in Example 1 was used as the metal soap, and the evaluation method was the same as that of Example 1 except that the intermediate transfer belt E was used instead of the intermediate transfer belt A described in Example 1.

Example 6
[Preparation of Intermediate Transfer Belt F]
It was produced by the same method except for the intermediate transfer belt A described in Example 1 and the shape of the convex portion on the surface. Height 0.1 [mu] m in mold inner surface, to produce a linear recess width 2 [mu] m, the area surrounded by the recess is adjusted to 3000 .mu.m ^2, the height on the surface 0.1 [mu] m, a width of 2 [mu] m An intermediate transfer belt F having linear convex portions and having an area surrounded by the convex portions of 3000 μm ² was obtained.
The metal soap A described in Example 1 was used as the metal soap, and the evaluation method was the same as that of Example 1 except that the intermediate transfer belt F was used instead of the intermediate transfer belt A described in Example 1.

Example 7
[Preparation of Intermediate Transfer Belt G]
It was produced by the same method except for the intermediate transfer belt A described in Example 1 and the shape of the convex portion on the surface. Height 0.1 [mu] m in mold inner surface, to produce a linear recess width 5 [mu] m, the area surrounded by the recess is adjusted to 3000 .mu.m ^2, the height on the surface 0.1 [mu] m, a width of 5 [mu] m An intermediate transfer belt G in which linear convex portions exist and an area surrounded by the convex portions is 3000 μm ² was obtained.
The metal soap A described in Example 1 was used as the metal soap, and the evaluation method was the same as that of Example 1 except that the intermediate transfer belt G was used instead of the intermediate transfer belt A described in Example 1.

Example 8
[Preparation of Intermediate Transfer Belt H]
It was produced by the same method except for the intermediate transfer belt A described in Example 1 and the shape of the convex portion on the surface. A linear recess having a height of 0.1 μm and a width of 1 μm is formed on the inner surface of the mold, and the area surrounded by the recess is adjusted to be 1000 μm ^{2. The} surface has a height of 0.1 μm and a width of 1 μm. An intermediate transfer belt H having linear convex portions and an area surrounded by the convex portions being 1000 μm ² was obtained.
The metal soap A described in Example 1 was used as the metal soap, and the evaluation method was the same as that of Example 1 except that the intermediate transfer belt H was used instead of the intermediate transfer belt A described in Example 1.

Example 9
[Preparation of Intermediate Transfer Belt I]
It was produced by the same method except for the intermediate transfer belt A described in Example 1 and the shape of the convex portion on the surface. Height 0.1 [mu] m in mold inner surface, to produce a linear recess width 1 [mu] m, the area surrounded by the recess is adjusted to 15000Myuemu ^2, the height on the surface 0.1 [mu] m, a width of 1 [mu] m An intermediate transfer belt I having linear convex portions and an area surrounded by the convex portions being 15000 μm ² was obtained.
The metal soap A described in Example 1 was used as the metal soap, and the evaluation method was the same as that of Example 1 except that the intermediate transfer belt I was used instead of the intermediate transfer belt A described in Example 1.

Example 10
[Preparation of Intermediate Transfer Belt J]
It was produced by the same method except for the intermediate transfer belt A described in Example 1 and the shape of the convex portion on the surface. Height 0.1 [mu] m in mold inner surface, to produce a linear recess width 1 [mu] m, the area surrounded by the recess is adjusted to 30000Myuemu ^2, the height on the surface 0.1 [mu] m, a width of 1 [mu] m An intermediate transfer belt J having linear convex portions and an area surrounded by the convex portions being 30000 μm ² was obtained.
The metal soap A described in Example 1 was used as the metal soap, and the evaluation method was the same as that of Example 1 except that the intermediate transfer belt J was used instead of the intermediate transfer belt A described in Example 1.

Example 11
The intermediate transfer belt C described in Example 3 was used as the intermediate transfer belt.
[Preparation of metal soap B]
The metal soap A described in Example 1 is prepared in the same manner except for the ratio of zinc stearate and zinc palmitate. Metal soap B was obtained with zinc stearate and zinc palmitate in the proportions shown below.

<Metal soap constituent materials>
・ Zinc stearate 72.5 weight ratio ・ Zinc palmitate 27.5 weight ratio

<Evaluation method>
The evaluation method was the same as that of Example 1 except that metal soap B was used instead of metal soap A and intermediate transfer belt C was used instead of intermediate transfer belt A.

Example 12
The intermediate transfer belt C described in Example 3 was used as the intermediate transfer belt.
[Production of metal soap C]
The metal soap A described in Example 1 is prepared in the same manner except for the ratio of zinc stearate and zinc palmitate. Metal soap C was obtained with zinc stearate and zinc palmitate in the proportions shown below.

<Metal soap constituent materials>
-Zinc stearate 70 weight ratio-Zinc palmitate 30 weight ratio

<Evaluation method>
The evaluation method was the same as that of Example 1 except that metal soap C was used instead of metal soap A and intermediate transfer belt C was used instead of intermediate transfer belt A.

Example 13
The intermediate transfer belt C described in Example 3 was used as the intermediate transfer belt.
[Preparation of metal soap D]
The metal soap A described in Example 1 is prepared in the same manner except for the ratio of zinc stearate and zinc palmitate. Metal soap D was obtained with zinc stearate and zinc palmitate in the proportions shown below.

<Metal soap constituent materials>
・ Zinc stearate 40 weight ratio ・ Zinc palmitate 60 weight ratio

<Evaluation method>
The evaluation method was the same as that of Example 1 except that metal soap D was used instead of metal soap A and intermediate transfer belt C was used instead of intermediate transfer belt A.

Example 14
The evaluation method described in Example 3 was performed in the same manner except that the image forming apparatus (FIG. 2) was changed to the image forming apparatus (FIG. 3).

Example 15
The evaluation method described in Example 11 was performed in the same manner except that the image forming apparatus (FIG. 2) was changed to the image forming apparatus (FIG. 3).

○ Comparative Example 1
[Preparation of intermediate transfer belt K]
It was produced by the same method except for the intermediate transfer belt A described in Example 1 and the shape of the convex portion on the surface. Height 0.005μm to mold the inner surface, to produce a linear recess width 1 [mu] m, the area surrounded by the recess is adjusted to 3000 .mu.m ^2, height 0.005μm on the surface, the width of 1 [mu] m An intermediate transfer belt K having linear convex portions and having an area surrounded by the convex portions of 3000 μm ² was obtained.
The metal soap A described in Example 1 was used as the metal soap, and the evaluation method was the same as that of Example 1 except that the intermediate transfer belt K was used instead of the intermediate transfer belt A described in Example 1.

○ Comparative Example 2
[Preparation of Intermediate Transfer Belt L]
It was produced by the same method except for the intermediate transfer belt A described in Example 1 and the shape of the convex portion on the surface. Height 1.5 [mu] m in mold inner surface, to produce a linear recess width 1 [mu] m, the area surrounded by the recess is adjusted to 3000 .mu.m ^2, the height on the surface 1.5 [mu] m, a width of 1 [mu] m An intermediate transfer belt L in which linear convex portions exist and an area surrounded by the convex portions is 3000 μm ² was obtained.
The metal soap A described in Example 1 was used as the metal soap, and the evaluation method was the same as that of Example 1 except that the intermediate transfer belt L was used instead of the intermediate transfer belt A described in Example 1.

○ Comparative Example 3
[Preparation of Intermediate Transfer Belt M]
It was produced by the same method except for the intermediate transfer belt A described in Example 1 and the shape of the convex portion on the surface. Height 0.1μm to mold the inner surface, to produce a linear recess width 0.4 .mu.m, the area surrounded by the recess is adjusted to 3000 .mu.m ^2, height 0.1μm on the surface, the width An intermediate transfer belt M having a linear convex part of 0.4 μm and an area surrounded by the convex part of 3000 μm ² was obtained.
The metal soap A described in Example 1 was used as the metal soap, and the evaluation method was the same as that of Example 1 except that the intermediate transfer belt M was used instead of the intermediate transfer belt A described in Example 1.

○ Comparative Example 4
[Preparation of Intermediate Transfer Belt N]
It was produced by the same method except for the intermediate transfer belt A described in Example 1 and the shape of the convex portion on the surface. Height 0.1 [mu] m in mold inner surface, to produce a linear recess width 6 [mu] m, the area surrounded by the recess is adjusted to 3000 .mu.m ^2, the height on the surface 0.1 [mu] m, a width of 6 [mu] m An intermediate transfer belt N in which linear convex portions exist and an area surrounded by the convex portions is 3000 μm ² was obtained.
The metal soap A described in Example 1 was used as the metal soap, and the evaluation method was the same except that the intermediate transfer belt N was used instead of the intermediate transfer belt A described in Example 1.

○ Comparative Example 5
[Preparation of Intermediate Transfer Belt O]
It was produced by the same method except for the intermediate transfer belt A described in Example 1 and the shape of the convex portion on the surface. Height 0.1 [mu] m in mold inner surface, to produce a linear recess width 1 [mu] m, the area surrounded by the recess is adjusted to 900 .mu.m ^2, the height on the surface 0.1 [mu] m, a width of 1 [mu] m An intermediate transfer belt O having linear convex portions and an area surrounded by the convex portions being 900 μm ² was obtained.
The metal soap A described in Example 1 was used as the metal soap, and the evaluation method was the same as that of Example 1 except that the intermediate transfer belt O was used instead of the intermediate transfer belt A described in Example 1.

○ Comparative Example 6
[Preparation of Intermediate Transfer Belt P]
It was produced by the same method except for the intermediate transfer belt A described in Example 1 and the shape of the convex portion on the surface. Height 0.1 [mu] m in mold inner surface, to produce a linear recess width 1 [mu] m, the area surrounded by the recess is adjusted to 35000Myuemu ^2, the height on the surface 0.1 [mu] m, a width of 1 [mu] m An intermediate transfer belt P in which linear convex portions exist and an area surrounded by the convex portions is 35000 μm ² was obtained.
The metal soap A described in Example 1 was used as the metal soap, and the evaluation method was the same as that of Example 1 except that the intermediate transfer belt P was used instead of the intermediate transfer belt A described in Example 1.

○ Comparative Example 7
The intermediate transfer belt C described in Example 3 was used as the intermediate transfer belt.
[Production of metal soap E]
Zinc stearate (primary particle size: 0.18μm) is heated to 145 ° C and melted, and molten metal soap is poured into the mold and cooled to produce a 40mm x 8mm x 350mm long metal soap block. (Because it is made by melt molding, the degree of compression is 100%). This lubrication block was attached to a base material for metal soap with an adhesive to obtain metal soap E.

<Evaluation method>
The evaluation method was the same as that of Example 1 except that metal soap E was used in place of metal soap A and intermediate transfer belt C was used in place of intermediate transfer belt A.

  Table 1 shows the evaluation results of the above examples and comparative examples. The criteria for output image evaluation in the table indicate that ◎ indicates that an abnormal image is not seen and a high-quality image is obtained. ○ Although there was no abnormal image when the linear velocity of image formation was 250 mm / sec, there were some spots where dots were flowing slightly when viewed with a magnifier when the linear velocity was increased to 450 mm / sec. Shows what you did. X indicates that an abnormal image was observed beyond the allowable range.

From the above results, the exposure rate of the surface of the intermediate transfer belt after applying metal soap for 5 minutes in the absence of toner and paper is 30% or less, preferably 20% or less, more preferably 10% or less. The intermediate transfer belt having an element content of 1.7 atm% or more and 2.5 atm% or less was found to have an appropriate amount of metal soap applied uniformly on the surface, so that there was no abnormal image and a high-quality full-color image could be obtained. . In order to realize this form, a linear protrusion on the surface of the intermediate transfer belt has a height of 0.01 μm to 1 μm, a width of 0.5 μm to 5 μm, more preferably a height of 0.02 μm to 0.1 μm, present in width 1μm or 2μm or less, enclosed area 1000 .mu.m ² or more 30000Myuemu ² or less in the protruding portion, more preferably 3000 .mu.m ² or more 15000Myuemu ² or less, at the same time the metal soap is a mixture of zinc stearate and zinc palmitate It was found that the mixing ratio is more preferably 73:27 weight ratio or more and 45:55 weight ratio or less.

  According to the present invention, a long-life intermediate transfer method for full-color electrophotography that provides stable high-quality full-color images with stable electrical characteristics, excellent wear resistance, no abnormal images such as voids, density unevenness, and color unevenness. In addition, an electrophotographic image forming method using the same, an intermediate transfer system for full-color electrophotography, and an image forming apparatus using the same can be provided.

(About Figure 2)
P Transfer paper L Exposure means 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 Toner image density sensor 210 Belt transport device 230 Revolver developing unit 231Y Y developing machine 231K Bk development Machine 231C C developing machine 231M M developing machine 270 fixing device 271 fixing roller 272 fixing roller 500 intermediate transfer unit 501 intermediate transfer belt 503 toner seal member 504 belt cleaning blade 505 metal soap application brush 506 metal soap 507 primary transfer bias roller 508 belt Driving roller 509 Belt tension roller 510 Secondary transfer counter roller 511 Cleaning counter roller 512 Feed bag current detection roller 513 Toner image 14 optical sensor 600 the secondary transfer unit 601 transfer sheet guide plate 605 secondary transfer bias roller 606 transfer paper discharger 608 cleaning blade 610 a registration roller 801 primary transfer power supply 802 secondary transfer power supply (for Fig. 3)
P transfer paper 10 printer main body 12 image writing unit 13 image forming unit 14 paper feeding unit 15 fixing device 16 registration roller 20BK developing device 20M developing device 20Y developing device 20C developing device 21BK photoconductor 21M photoconductor 21Y photoconductor 21C photoconductor 22 Intermediate transfer belt 23BK Primary transfer bias roller 23M Primary transfer bias roller 23Y Primary transfer bias roller 23C Primary transfer bias roller 24 Belt drive roller 25 Belt cleaning device 26 Belt driven roller 27 Static elimination means 28 Optical sensor 50 Transfer conveyance belt 60 Secondary transfer bias roller 70 Bias roller

JP-A-8-95455 Japanese Patent No. 3753909 JP 2005-316231 A JP 2004-361694 A JP 2005-17469 A JP 2005-249901 A JP-A-2005-004051 JP 2004-198662 A

Claims (12)

An electrophotographic intermediate transfer method for performing an intermediate transfer using an electrophotographic intermediate transfer belt containing nitrogen element on the surface,
A metal soap application step of applying metal soap to the intermediate transfer belt for electrophotography,
In the metal soap application step, the content A (atm%) of the nitrogen element obtained by measuring the surface of the intermediate transfer belt before applying the metal soap by XPS, and the state where the toner and paper are not present in the metal soap The intermediate transfer belt exposure rate (B / A) × 100 (calculated from the nitrogen element content B (atm%) obtained by measuring the surface of the intermediate transfer belt after XPS for 5 minutes with XPS. %) Is 30% or less, an intermediate transfer method for electrophotography.   2. The electrophotographic intermediate transfer method according to claim 1, wherein the metal soap is a mixture of zinc stearate and zinc palmitate.   The electrophotographic intermediate transfer method according to claim 2, wherein the mixing ratio of the zinc stearate and the zinc palmitate is 73:27 or more and 45:55 or less by weight. The intermediate transfer belt has a linear protrusion on the surface,
4. The electrophotographic intermediate transfer method according to claim 1, wherein the convex portion has a height of 0.01 μm to 1 μm and a width of 0.5 μm to 5 μm. 5. That the image forming region of the intermediate transfer belt is surrounded by a line-shaped convex portion, it is a plurality of small regions divided, and the individual areas of the divided small regions is 1000 .mu.m ² or more 30000Myuemu ² or less The electrophotographic intermediate transfer method according to claim 1, wherein the method is an intermediate transfer method for electrophotography.   An electrophotographic image forming method comprising the electrophotographic intermediate transfer method according to claim 1. An electrophotographic intermediate transfer system in which a metal soap is applied to an electrophotographic intermediate transfer belt containing nitrogen on the surface,
The content A (atm%) of nitrogen element obtained by measuring the surface of the intermediate transfer belt before applying the metal soap by XPS, and after applying the metal soap for 5 minutes in the absence of toner and paper The intermediate transfer belt exposure rate (B / A) × 100 (%) calculated from the nitrogen element content B (atm%) obtained by measuring the surface of the intermediate transfer belt with XPS is 30% or less. An intermediate transfer system for electrophotography, characterized in that it exists.   The intermediate transfer system for electrophotography according to claim 7, wherein the metal soap is a mixture of zinc stearate and zinc palmitate.   The electrophotographic intermediate transfer system according to claim 8, wherein the mixing ratio of the zinc stearate and the zinc palmitate is 73:27 to 45:55 weight ratio. The intermediate transfer belt has a linear protrusion on the surface,
10. The electrophotographic intermediate transfer system according to claim 7, wherein the convex portion has a height of 0.01 μm to 1 μm and a width of 0.5 μm to 5 μm. That the image forming region of the intermediate transfer belt is surrounded by a line-shaped convex portion, it is a plurality of small regions divided, and the individual areas of the divided small regions is 1000 .mu.m ² or more 30000Myuemu ² or less The intermediate transfer system for electrophotography according to any one of claims 7 to 10, wherein the intermediate transfer system is used.   An electrophotographic image forming apparatus comprising the electrophotographic intermediate transfer system according to claim 7.

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