Intermediate transfer belt, transfer device, and image forming apparatus

Abstract

To provide an intermediate transfer belt that can prevent turn-up of a blade that is in contact with an outer peripheral surface of the intermediate transfer belt to clean the outer peripheral surface.SOLUTION: An intermediate transfer belt contains resin, conductive carbon particles, alkyl silicone oil and a modified form thereof. An outer peripheral surface is formed with an area different in content of the alkyl silicone oil and the modified form thereof. When an amount of silicon (atomic%) is measured for the outer peripheral surface along an axial direction by using the X-ray photoelectron spectroscopy, the amount of silicon periodically increases and decreases along the axial direction, and a distance between peak tops in the increase and decrease period of the amount of silicon is 0.1 mm or more and 5.0 mm or less.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present disclosure relates to an intermediate transfer belt, a transfer device, and an image forming apparatus. [Background technology]

[0002] In an image forming apparatus (such as a copier, a facsimile, or a printer) using an electrophotographic method, a toner image formed on the surface of an image carrier is transferred to the surface of a recording medium and fixed on the recording medium to form an image. Note that, for example, a transfer device equipped with a conductive intermediate transfer belt such as an intermediate transfer belt is used to transfer such a toner image to the recording medium.

[0003] For example, Patent Document 1 discloses an image forming apparatus including a recording material carrier that carries and transports a recording material, an image forming means that forms a toner image on the recording material carried by the recording material carrier, and a cleaning means that cleans the recording material carrier, the cleaning means having a cleaning blade, and using the recording material carrier such that when the pressure of the cleaning blade against the recording material carrier is set to 15 g / cm or more and 100 g / cm, the initial surface roughness Rz of the recording material carrier is 0.01 μm or more and 1.0 μm or less, and the average surface roughness Rz after 10,000 rotations in actual operation is 0.01 μm or more and 1.5 μm or less.

[0004] Patent Document 2 discloses an image forming apparatus having an image transport body that carries and transports a toner image directly or via a transfer material, and a cleaning member that comes into contact with the surface of the image transport body and rubs the surface of the moving image transport body to scrape off toner from the surface of the image transport body, wherein a lubricant is added to a surface layer that forms the surface of the image transport body, grooves are formed on the surface of the image transport body along the moving direction of the surface of the image transport body, and the image forming apparatus is characterized in that, when the average particle diameter of the lubricant is d and the depth of the protruding valley on the surface of the image transport body when measured in a direction approximately perpendicular to the moving direction of the surface of the image transport body is Rvk, the relationship d>Rvk is satisfied. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2001-305879 A [Patent Document 2] JP 2015-106138 A Summary of the Invention [Problem to be solved by the invention]

[0006] The object of the present disclosure is to provide an intermediate transfer belt which includes a resin, conductive carbon particles, and an alkyl silicone oil and a modified product thereof, and in which regions having different contents of the alkyl silicone oil and the modified product thereof are formed on the outer peripheral surface, and in which, when the silicon amount (atomic %) of the outer peripheral surface is measured along the axial direction using X-ray photoelectron spectroscopy, the silicon amount increases and decreases periodically along the axial direction, and in which the distance between the peak tops in the cycle of increase and decrease in the silicon amount is less than 0.1 mm or more than 5.0 mm, the intermediate transfer belt can suppress curling of a blade that comes into contact with the outer peripheral surface to clean the outer peripheral surface of the intermediate transfer belt. [Means for solving the problem]

[0007] The above problems are solved by the following means. <1> The conductive material includes a resin, conductive carbon particles, and an alkyl silicone oil or a modified product thereof, On the outer peripheral surface, regions having different contents of the alkyl silicone oil and its modified product are formed, When the amount of silicon (atomic %) on the outer peripheral surface is measured along the axial direction using X-ray photoelectron spectroscopy, the amount of silicon periodically increases and decreases along the axial direction, and the distance between the peak tops in the period of increase and decrease in the amount of silicon is 0.1 mm or more and 5.0 mm or less. <2> The peak top distance is 0.1 mm or more and 3.0 mm or less. <1> The intermediate transfer belt according to claim 1. <3> The difference between the peak top and the peak bottom in the cycle of increase and decrease of the silicon content is 0.1 Atomic% or more and 5.0 Atomic% or less. <1> or <2> The intermediate transfer belt according to claim 1. <4> The distance between the peak tops is 0.1 mm or more and 3.0 mm or less, and the difference between the peak top and the peak bottom in the cycle of increase and decrease of the silicon amount is 0.1 Atomic% or more and 5.0 Atomic% or less. <1> The intermediate transfer belt according to claim 1. <5> the difference between the surface resistivity at the peak top and the surface resistivity at the peak bottom in the cycle of increase and decrease of the silicon amount is 0.03 log Ω / □ or less; <1> ~ <4> 2. The intermediate transfer belt according to claim 1 . <6> the difference between the surface resistivity at the peak top and the surface resistivity at the peak bottom in the cycle of increase and decrease of the silicon amount is 0.02 log Ω / □ or less; <5> The intermediate transfer belt according to claim 1.

[0008] <7> <1> ~ <6> An intermediate transfer belt according to any one of the above items; a blade that comes into contact with an outer peripheral surface of the intermediate transfer belt and cleans the outer peripheral surface; a primary transfer device having a primary transfer member for primarily transferring a toner image formed on a surface of an image carrier onto an outer peripheral surface of the intermediate transfer belt; a secondary transfer device that is disposed in contact with an outer peripheral surface of the intermediate transfer belt and has a secondary transfer member that secondarily transfers the toner image transferred onto the outer peripheral surface of the intermediate transfer belt onto a surface of a recording medium; A transfer device comprising: <8> An image carrier; a charging device for charging the surface of the image carrier; an electrostatic latent image forming device for forming an electrostatic latent image on a charged surface of the image carrier; a developing device that contains a developer containing a toner and develops an electrostatic latent image formed on the surface of the image carrier with the developer to form a toner image; transferring the toner image onto a surface of a recording medium; <7> A transfer device according to the present invention; An image forming apparatus comprising: Effect of the Invention

[0009] <1> According to the invention, there is provided an intermediate transfer belt which includes a resin, conductive carbon particles, and an alkyl silicone oil and a modified product thereof, and on the outer peripheral surface, there are formed regions with different contents of the alkyl silicone oil and the modified product thereof, and when the silicon amount (atomic %) of the outer peripheral surface is measured along the axial direction using X-ray photoelectron spectroscopy, the silicon amount increases and decreases periodically along the axial direction, and the distance between the peak tops in the cycle of increase and decrease in the silicon amount is less than 0.1 mm or more than 5.0 mm, which can suppress curling of a blade that comes into contact with the outer peripheral surface to clean the outer peripheral surface of the intermediate transfer belt.

[0010] <2> or <4> According to the invention, an intermediate transfer belt is provided that can suppress curling of a blade that comes into contact with the outer peripheral surface of the intermediate transfer belt to clean the outer peripheral surface, compared to when the peak-to-top distance is greater than 3.0 and 5.0 mm or less. <3> or <4> According to the invention, an intermediate transfer belt is provided that can suppress curling of a blade that comes into contact with the outer peripheral surface of the intermediate transfer belt to clean the outer peripheral surface, compared to when the difference between the peak top and the peak bottom in the cycle of increase and decrease in silicon amount is less than 0.1 Atomic% or exceeds 5.0 Atomic%. <5> According to the present invention, an intermediate transfer belt having excellent transfer efficiency is provided, as compared with a case in which the difference between the surface resistivity at the peak top portion and the surface resistivity at the peak bottom portion exceeds 0.03 log Ω / □. <6> According to the present invention, an intermediate transfer belt is provided which has superior transfer efficiency compared to a belt in which the difference between the surface resistivity at the peak top and the surface resistivity at the peak bottom is greater than 0.02 log Ω / □ and not more than 0.03 log Ω / □.

[0011] <7> or <8> According to the invention, there is provided a transfer device or image forming device which includes a resin, conductive carbon particles, and an alkyl silicone oil and a modified product thereof, and on the outer peripheral surface, there are formed regions with different contents of the alkyl silicone oil and the modified product thereof, and when the silicon amount (atomic %) of the outer peripheral surface is measured along the axial direction using X-ray photoelectron spectroscopy, the silicon amount increases and decreases periodically along the axial direction, and the peak top distance in the cycle of increase and decrease of the silicon amount is less than 0.1 mm or more than 5.0 mm, and which can suppress curling of a blade which comes into contact with the outer peripheral surface of the intermediate transfer belt to clean the outer peripheral surface of the intermediate transfer belt. [Brief description of the drawings]

[0012] [Figure 1] 5A and 5B are schematic diagrams for explaining contact conditions between the intermediate transfer belt and the blade according to the embodiment. [Diagram 2] 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an embodiment of the present invention. [Diagram 3] 5 is a graph for explaining a cycle of increase and decrease in the amount of silicon on the outer circumferential surface of the intermediate transfer belt according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The present embodiment will be described below. The description and examples are merely illustrative of the embodiment, and are not intended to limit the scope of the embodiment.

[0014] In the numerical ranges described in the present embodiment, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range described in the present embodiment. In addition, in the numerical ranges described in the present embodiment, the upper or lower limit of the numerical range may be replaced with a value shown in the examples. In this embodiment, the term "process" includes not only an independent process, but also a process that cannot be clearly distinguished from other processes as long as the intended purpose of the process is achieved. When the embodiment is described with reference to the drawings, the configuration of the embodiment is not limited to the configuration shown in the drawings. Furthermore, the size of the members in each drawing is conceptual, and the relative relationship between the sizes of the members is not limited to this. In this embodiment, each component may contain multiple types of corresponding substances. When referring to the amount of each component in the composition in this embodiment, if multiple substances corresponding to each component are present in the composition, the amount refers to the total amount of the multiple substances present in the composition, unless otherwise specified.

[0015] <Intermediate transfer belt> The intermediate transfer belt according to this embodiment includes a resin, conductive carbon particles, and an alkyl silicone oil and a modified product thereof, and has regions on its outer peripheral surface that have different contents of the alkyl silicone oil and the modified product thereof. When the silicon content (atomic %) of the outer peripheral surface is measured along the axial direction using X-ray photoelectron spectroscopy, the silicon content increases and decreases periodically along the axial direction, and the distance between the peak tops in the cycle of increase and decrease in the silicon content is 0.1 mm or more and 5.0 mm or less. The outer peripheral surface refers to the surface onto which the toner image is transferred. In addition, "alkyl silicone oil and its modified product" is also collectively referred to as "alkyl silicone oil".

[0016] It is known that the outer peripheral surface of an intermediate transfer belt is made to have a high release property to improve the transfer efficiency. However, if the outer peripheral surface is simply made to have a high release property, the blade that comes into contact with the outer peripheral surface of the intermediate transfer belt to clean the outer peripheral surface may be curled up. This is presumably because the improvement in transfer efficiency reduces the amount of residual toner that penetrates into the contact area between the outer peripheral surface of the intermediate transfer belt and the blade, which can cause insufficient lubrication at the contact area, resulting in unstable operation of the edge of the blade.

[0017] As described above, the intermediate transfer belt according to the present embodiment contains alkyl silicone oil with high releasability. This reduces the non-electrostatic adhesion of the toner to the outer peripheral surface of the intermediate transfer belt, making it easier for the toner to be peeled off from the intermediate transfer belt. As a result, the intermediate transfer belt according to the present embodiment has high transfer efficiency. Furthermore, the intermediate transfer belt according to the present embodiment has a configuration in which an area with a different content of alkyl silicone oil is formed on its outer circumferential surface, and when the silicon amount (atomic%) is measured along the axial direction of the outer circumferential surface by X-ray photoelectron spectroscopy (XPS), the silicon amount increases and decreases periodically along the axial direction, and the peak top distance in the increase and decrease cycle of the silicon amount is 0.1 mm or more and 5.0 mm or less. In this configuration, the outer circumferential surface has a part with a large amount of alkyl silicone oil and a part with a small amount of alkyl silicone oil, so that residual toner, etc., can be appropriately inserted into the contact portion between the outer circumferential surface of the intermediate transfer belt and the blade, thereby reducing the friction of the edge portion of the blade, and further stabilizing the operation of the edge portion of the blade. As a result, it is presumed that the blade can be prevented from turning over. In addition, it is presumed that the cleaning property of the outer circumferential surface is improved because the operation of the edge portion of the blade is stabilized and the blade turning over is suppressed. Hereinafter, "the curling of the blade that comes into contact with the outer peripheral surface of the intermediate transfer belt in order to clean the outer peripheral surface" will be simply referred to as "curling of the blade".

[0018] [Preferred embodiment] Hereinafter, preferred aspects of the intermediate transfer belt according to the present embodiment will be described.

[0019] In the intermediate transfer belt according to this embodiment, from the viewpoint of further suppressing blade curling, the peak-to-top distance in the cycle of increase and decrease in silicon amount is preferably 0.1 mm or more and 3.0 mm or less, and more preferably 1.0 mm or more and 3.0 mm or less.

[0020] In the intermediate transfer belt according to this embodiment, from the viewpoint of further suppressing blade curling, the difference between the peak top and the peak bottom in the cycle of increase and decrease in the silicon amount is preferably 0.1 Atomic% or more and 5.0 Atomic% or less, and more preferably 0.5 Atomic% or more and 5.0 Atomic% or less.

[0021] In the intermediate transfer belt according to this embodiment, from the viewpoint of further suppressing blade curling, it is preferable that the distance between the peak tops in the cycle of increase and decrease in the silicon amount is 0.1 mm or more and 3.0 mm or less, and that the difference between the peak top and the peak bottom in the cycle of increase and decrease in the silicon amount is 0.1 Atomic% or more and 5.0 Atomic% or less.

[0022] Here, a method for measuring the silicon content using X-ray photoelectron spectroscopy (XPS) and a method for determining the distance between the peak tops in the cycle of increase and decrease in the silicon content and the difference between the peak top and the peak bottom in the cycle of increase and decrease in the silicon content will be described. The amount of silicone by XPS is measured, for example, using a JPS-9000MX manufactured by JEOL Ltd., with an acceleration voltage of 10 kV, an emission current of 10 mA, and measurement energy of 0 to 1100 eV. The cumulative value of the peak size of each element detected in a wide scan is taken as 100%, and the peak ratio of each element is taken as the atomic % of each element. The amount of silicon is defined by the Si 2p3 / 2 peak that appears near 102 eV. Typically, the measurement in the belt axial direction is performed by moving the belt axially every 0.1 mm and repeating the same measurement.

[0023] In the intermediate transfer belt according to this embodiment, the amount of silicon on the outer peripheral surface is measured using the method described above. When the relationship between the measured amount of silicon and the axial (width) distance of the outer peripheral surface of the intermediate transfer belt is plotted on a graph, a periodic increase and decrease in the amount of silicon is observed, as shown in FIG. 3. Here, Figure 3 is a graph to explain the cycle of increase and decrease in the amount of silicon on the outer peripheral surface of the intermediate transfer belt in this embodiment, where the vertical axis shows the amount of silicon and the horizontal axis shows the axial (width) distance of the outer peripheral surface of the intermediate transfer belt. As shown in FIG. 3, the peak top distance in the silicon content increase / decrease cycle is calculated by finding the peak top distance X between adjacent peaks for 10 points in the silicon content increase / decrease cycle, and averaging the distances. The difference between the peak top and the peak bottom in the cycle of increase and decrease of the silicon amount is calculated by finding the difference Y between adjacent peak tops and peak bottoms for 10 points in the cycle of increase and decrease of the silicon amount, as shown in FIG. 3, and averaging them.

[0024] In the intermediate transfer belt according to this embodiment, the difference between the surface resistivity at the peak top and the surface resistivity at the peak bottom during the cycle of increase and decrease in the amount of silicon is preferably 0.03 log Ω / □ or less, and more preferably 0.02 log Ω / □ or less. In addition, in the cycle of increase and decrease of the silicon amount, the difference between the surface resistivity at the peak top and the surface resistivity at the peak bottom is preferably as small as possible, and is most preferably zero. In the intermediate transfer belt according to the present embodiment, from the viewpoint of suppressing unevenness in image quality, it is preferable that the difference in surface resistivity is small as described above, even if a region with a different content of alkyl silicone oil is formed on the outer peripheral surface. When a region with a different content of alkyl silicone oil is formed on the outer peripheral surface, this intermediate transfer belt is considered to have a conduction mechanism by two routes, that is, the charge held by the alkyl silicone oil on this outer peripheral surface and the charge transmitted through the alkyl silicone oil-belt base (resin component) interface. The surface resistivity of such an intermediate transfer belt is the sum of both of the above-mentioned charge conduction mechanisms, and it is considered that the contribution of the charge transmitted through the latter interface is particularly large. From this, it is presumed that the intermediate transfer belt according to the present embodiment has a small difference in surface resistivity even if a region with a different content of alkyl silicone oil is formed on the outer peripheral surface. In this way, the intermediate transfer belt according to the present embodiment can also increase transfer efficiency because the difference in surface resistivity of the outer peripheral surface is small.

[0025] Here, a method for measuring the surface resistivity of the belt will be described. From the viewpoint of improving transferability, the common logarithm of the surface resistivity when a voltage of 500 V is applied for 10 seconds to the outer peripheral surface of the intermediate transfer belt is preferably 9.5 (log Ω / suq.) or more and 15.0 (log Ω / suq.) or less, more preferably 10.0 (log Ω / suq.) or more and 14.0 (log Ω / suq.) or less, and particularly preferably 11.0 (log Ω / suq.) or more and 13.5 (log Ω / suq.) or less. The surface resistivity log Ω / suq. is expressed as the logarithm of the resistance value per area, and is also expressed as log(Ω / suq.), log Ω / square, log Ω / □, etc. The surface resistivity when a voltage of 500 V is applied to the outer peripheral surface of the intermediate transfer belt for 10 seconds is measured by the following method. A microammeter (R8430A manufactured by Advantest) is used as the resistance measuring device, and a UR probe (manufactured by Mitsubishi Chemical Analytech Co., Ltd.) is used as the probe, and the surface resistivity (logΩ / suq.) of the outer peripheral surface of the intermediate transfer belt is measured at six equally spaced points in the circumferential direction of the outer peripheral surface of the intermediate transfer belt, the probe is continuously swept in the width direction, and the measurements are taken at a voltage of 500V, an application time of 10 seconds, and a pressure of 1kgf, and the average value is calculated. The measurements are also performed in an environment with a temperature of 22°C and a humidity of 55%RH.

[0026] [Configuration of intermediate transfer belt] The intermediate transfer belt according to this embodiment contains a resin, conductive carbon particles, and alkyl silicone oil and its modified product, and may be a single layer or a laminate, so long as the outer peripheral surface has the configuration described above. When the intermediate transfer belt is a single layer, the single layer contains a resin, conductive carbon particles, alkyl silicone oil and its modified product, and the outer circumferential surface has the above-mentioned structure. In addition, when the intermediate transfer belt is a laminate, the laminate preferably has, for example, a substrate layer and a surface layer that is the outermost layer provided on the substrate layer. The laminate may have another layer between the substrate layer and the surface layer. In the case where the intermediate transfer belt is a laminate having a substrate layer and a surface layer, it is preferable that the surface layer contains a resin, conductive carbon particles, and an alkyl silicone oil and a modified product thereof, and the outer circumferential surface thereof has the above-mentioned configuration. In this case, the substrate layer may contain a resin, conductive carbon particles, and an alkyl silicone oil and a modified product thereof, or may contain a resin and conductive carbon particles but not an alkyl silicone oil and a modified product thereof. In addition, the surface layer may be formed on the entire surface of the substrate layer, or may be formed partially. In addition, the resin, conductive carbon particles, and alkyl silicone oil and a modified product thereof contained in the substrate layer and the surface layer may be the same or different.

[0027] <Resin> Examples of resins contained in the intermediate transfer belt according to this embodiment include polyimide resin, polyamideimide resin, aromatic polyetherketone resin, polyphenylene sulfide resin, polyetherimide resin, polyester resin, polyamide resin, and polycarbonate resin.

[0028] (Polyimide resin) Examples of polyimide resins include imidized products of polyamic acids (precursors of polyimide resins), which are polymers of tetracarboxylic dianhydrides and diamine compounds. An example of the polyimide resin is a resin having a structure represented by the following general formula (I).

[0029] [ka]

[0030] In general formula (I), R 1 represents a tetravalent organic group, R 2 represents a divalent organic group. R 1 Examples of the tetravalent organic group represented by the formula (1) include an aromatic group, an aliphatic group, a cyclic aliphatic group, a group in which an aromatic group and an aliphatic group are combined, and groups in which these groups are substituted. Specific examples of the tetravalent organic group include residues of tetracarboxylic dianhydrides, which will be described later. R 2 Examples of the divalent organic group represented by the formula (1) include an aromatic group, an aliphatic group, a cyclic aliphatic group, a group in which an aromatic group and an aliphatic group are combined, and a group in which these groups are substituted. Specific examples of the divalent organic group include residues of diamine compounds described below.

[0031] Specific examples of tetracarboxylic dianhydrides used as raw materials for polyimide resins include pyromellitic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,3,3',4-biphenyltetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,2'-bis(3,4-dicarboxyphenyl)sulfonic dianhydride, perylene-3,4,9,10-tetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl)ether dianhydride, and ethylenetetracarboxylic dianhydride.

[0032] Specific examples of diamine compounds used as raw materials for polyimide resins include 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 3,3'-dichlorobenzidine, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 1,5-diaminonaphthalene, m-phenylenediamine, p-phenylenediamine, 3,3'-dimethyl 4,4'-biphenyldiamine, benzidine, and 3,3'-dimethyl Benzidine, 3,3'-dimethoxybenzidine, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenylpropane, 2,4-bis(β-amino tert-butyl)toluene, bis(p-β-amino-tert-butylphenyl)ether, bis(p-β-methyl-δ-aminophenyl)benzene, bis-p-(1,1-dimethyl-5-amino-pentyl)benzene, 1-isopropyl-2,4-m-phenylenediamine, m-xylylenediamine, p-xylylenediamine, di(p -aminocyclohexyl)methane, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, diaminopropyltetramethylene, 3-methylheptamethylenediamine, 4,4-dimethylheptamethylenediamine, 2,11-diaminododecane, 1,2-bis-3-aminopropoxyethane, 2,2-dimethylpropylenediamine, 3-methoxyhexamethylenediamine, 2,5-dimethylheptamethylenediamine, Examples include 3-methylheptamethylenediamine, 5-methylnonamethylenediamine, 2,17-diaminoeicosadecane, 1,4-diaminocyclohexane, 1,10-diamino-1,10-dimethyldecane, 12-diaminooctadecane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, piperazine, H2N(CH2)3O(CH2)2O(CH2)NH2, H2N(CH2)3S(CH2)3NH2, and H2N(CH2)3N(CH3)2(CH2)3NH2.

[0033] (Polyamide-imide resin) The polyamide-imide resin includes a resin having repeating imide bonds and amide bonds. More specifically, the polyamide-imide resin may be a polymer of a trivalent carboxylic acid compound (also called tricarboxylic acid) having an acid anhydride group, and a diisocyanate compound or a diamine compound.

[0034] As the tricarboxylic acid, trimellitic anhydride and its derivatives are preferable. In addition to the tricarboxylic acid, tetracarboxylic dianhydride, aliphatic dicarboxylic acid, aromatic dicarboxylic acid, etc. may be used in combination.

[0035] Examples of the diisocyanate compound include 3,3'-dimethylbiphenyl-4,4'-diisocyanate, 2,2'-dimethylbiphenyl-4,4'-diisocyanate, biphenyl-4,4'-diisocyanate, biphenyl-3,3'-diisocyanate, biphenyl-3,4'-diisocyanate, 3,3'-diethylbiphenyl-4,4'-diisocyanate, 2,2'-diethylbiphenyl-4,4'-diisocyanate, 3,3'-dimethoxybiphenyl-4,4'-diisocyanate, 2,2'-dimethoxybiphenyl-4,4'-diisocyanate, naphthalene-1,5-diisocyanate, and naphthalene-2,6-diisocyanate. The diamine compound may be a compound having a structure similar to that of the above-mentioned isocyanate, but having an amino group instead of the isocyanato group.

[0036] (Aromatic polyether ether ketone resin) Examples of aromatic polyether ether ketone resins include resins in which aromatic rings such as benzene rings are linearly bonded by ether bonds and ketone bonds, and in which the bonds are arranged in the following order: ether bond, ether bond, ketone bond.

[0037] (Polyphenylene sulfide resin) An example of the polyphenylene sulfide resin is a resin in which groups having benzene rings and sulfur atoms are alternately bonded. Examples of the group having a benzene ring include p-phenylene, m-phenylene, o-phenylene, alkyl-substituted phenylene, phenyl-substituted phenylene, halogen-substituted phenylene, amino-substituted phenylene, and amido-substituted phenylene.

[0038] (Polyetherimide resin) An example of the polyetherimide resin is a polymer of an aromatic bis(etherdicarboxylic acid) and a diamine. Examples of aromatic bis(ether dicarboxylic acids include 2,2-bis[4-(2,3-dicarboxyphenoxy)phenyl]propane and 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane. The diamine includes 4,4'-diaminodiphenylmethane, metaphenylenediamine, and the like.

[0039] Among these, the resin contained in the intermediate transfer belt is preferably an imide-based resin such as a polyimide resin, a polyamideimide resin, or a polyetherimide resin, more preferably contains at least one selected from the group consisting of a polyimide resin and a polyamideimide resin, and further preferably contains a polyimide resin.

[0040] The intermediate transfer belt may contain only one type of resin, or may contain two or more types of resin.

[0041] In the intermediate transfer belt which is a single layer, the resin content in the single layer is preferably from 48% by mass to 91% by mass, more preferably from 55% by mass to 89% by mass, and even more preferably from 65% by mass to 84% by mass, from the viewpoints of mechanical strength, volume resistivity adjustment, and the like. In the intermediate transfer belt which is a laminate, the resin content in the surface layer is preferably from 48% by mass to 91% by mass, more preferably from 55% by mass to 89% by mass, and even more preferably from 65% by mass to 84% by mass, from the viewpoints of mechanical strength and volume resistivity adjustment. In the intermediate transfer belt which is a laminate, the resin content in the base layer is preferably from 60% by mass to 95% by mass, more preferably from 70% by mass to 90% by mass, and even more preferably from 70% by mass to 80% by mass, from the viewpoints of mechanical strength, volume resistivity adjustment, and the like.

[0042] <Conductive carbon particles> The conductive carbon particles contained in the intermediate transfer belt according to this embodiment include, for example, carbon black. Examples of carbon black include ketjen black, oil furnace black, channel black, acetylene black, etc. As the carbon black, surface-treated carbon black (hereinafter also referred to as "surface-treated carbon black") may be used. Surface-treated carbon black can be obtained by imparting, for example, a carboxy group, a quinone group, a lactone group, a hydroxy group, etc. to its surface. Examples of the surface treatment method include an air oxidation method in which the carbon black is reacted by contacting with air in a high-temperature atmosphere, a method in which the carbon black is reacted with nitrogen oxides or ozone at room temperature (e.g., 22°C), and a method in which the carbon black is oxidized with air in a high-temperature atmosphere and then oxidized with ozone at a low temperature.

[0043] The number average primary particle size of the conductive carbon particles is, for example, 2 nm or more and 40 nm or less, and from the viewpoints of dispersibility, mechanical strength, volume resistivity, film-forming properties, etc., it is preferably 8 nm or more and 30 nm or less. When the intermediate transfer belt according to the present embodiment is a laminate, the number average primary particle size of the conductive carbon particles contained in the surface layer is preferably smaller than the number average primary particle size of the conductive carbon particles contained in the base layer.

[0044] The number average primary particle size of the conductive carbon particles is measured by the following method. First, a measurement sample having a thickness of 100 nm is taken from each layer of the obtained belt using a microtome, and the measurement sample is observed using a TEM (transmission electron microscope).Then, the diameter of a circle equal to the projected area of ​​each of 50 conductive carbon particles (i.e., the equivalent circle diameter) is taken as the particle diameter, and the average value is taken as the number-average primary particle diameter.

[0045] The conductive carbon particles contained in the intermediate transfer belt may be of one type or of two or more types.

[0046] In the intermediate transfer belt which is a single layer, the content of the conductive carbon particles in the single layer is preferably from 8% by mass to 45% by mass, more preferably from 10% by mass to 38% by mass, and even more preferably from 13% by mass to 30% by mass, from the viewpoints of ensuring strength and adjusting volume resistivity. In the intermediate transfer belt which is a laminate, the content of the conductive carbon particles in the surface layer is preferably from 8% by mass to 45% by mass, more preferably from 10% by mass to 38% by mass, and even more preferably from 13% by mass to 30% by mass, from the viewpoints of ensuring strength and adjusting volume resistivity. In the intermediate transfer belt which is a laminate, the content of the conductive carbon particles in the base layer is preferably from 5% by mass to 40% by mass, more preferably from 10% by mass to 30% by mass, and even more preferably from 20% by mass to 30% by mass, from the viewpoints of dispersibility, mechanical strength, and volume resistivity adjustment.

[0047] <Alkyl silicone oil and its modified form> The alkyl silicone oil and its modified product contained in the intermediate transfer belt according to the present embodiment refer to an oil having a siloxane bond with an alkyl group and a modified product of such an oil. Specific examples of the alkyl silicone oil and its modified product include dimethyl silicone oil and its modified product. The modified dimethyl silicone oil refers to a compound in which at least a portion of the methyl groups in the dimethyl silicone oil have been substituted with an organic group.

[0048] The organic group of the modified dimethyl silicone oil is not particularly limited as long as it is a group having a carbon atom. Examples of the organic group include a polyether group, a polyol group, a polyester group, an acrylic group, a fatty acid ester group, a phenyl group, a fluoro group, an alkyl group, and an aralkyl group. Among these, polyether groups are preferred from the viewpoint of improving releasability on the outer circumferential surface of the intermediate transfer belt. Specifically, the modified dimethyl silicone oil is preferably a polyether modified dimethyl silicone oil.

[0049] The modified dimethylsilicone oil may be a side-chain-type modified silicone oil in which an organic group is bonded to a side chain of dimethylsilicone oil, a single-end-type modified silicone oil in which an organic group is bonded to one end of dimethylsilicone oil, a double-end-type modified silicone oil in which an organic group is bonded to each of both ends of dimethylsilicone oil, or a side-chain double-end-type modified silicone oil in which an organic group is bonded to the side chain and both ends of dimethylpolysiloxane.

[0050] The viscosity (kinetic viscosity) of alkyl silicone oil and its modified form at 25°C is not particularly limited. 2 / s or more 100mm 2 From the viewpoint of uniform dispersion, 10 mm 2 / s or more 50mm 2 / s or less is preferable. The viscosity of the alkyl silicone oil and its modified product is measured using a B-8L type viscometer manufactured by Tokyo Keiki.

[0051] In the intermediate transfer belt which is a single layer, the content of the alkyl silicone oil and its modified product in the single layer is preferably from 1 to 7% by mass, more preferably from 3 to 5% by mass. In the intermediate transfer belt which is a laminate, the content of the alkyl silicone oil and its modified product in the surface layer is preferably from 1 to 7% by mass, more preferably from 3 to 5% by mass. In the intermediate transfer belt which is a laminate, the content of the alkyl silicone oil and its modified product in the base layer is not particularly limited, and may be less than the content of the alkyl silicone oil and its modified product in the surface layer, or may be zero.

[0052] <Other ingredients> The intermediate transfer belt according to the present embodiment may contain other components in addition to the resin, the conductive carbon particles, and the alkyl silicone oil and its modified product. Examples of other components include conductive agents other than conductive carbon particles, silicone oils other than alkyl silicone oils and modified forms thereof, fillers for improving the strength of the belt, antioxidants for preventing thermal deterioration of the belt, surfactants for improving fluidity, and heat-resistant anti-aging agents.

[0053] <Characteristics of the intermediate transfer belt> (Thickness of intermediate transfer belt) From the viewpoint of the mechanical strength of the belt, the thickness of the intermediate transfer belt is preferably 60 μm or more and 120 μm or less, and more preferably 80 μm or more and 120 μm or less. The thickness of each layer is measured as follows. That is, the cross section of the intermediate transfer belt in the thickness direction is observed by an optical microscope or a scanning electron microscope, the thickness of the layer to be measured is measured at 10 points, and the average value is regarded as the thickness.

[0054] (Volume resistivity of intermediate transfer belt) From the viewpoint of improving transferability, the common logarithm of the volume resistivity when a voltage of 500 V is applied to the intermediate transfer belt for 10 seconds is preferably 9.0 (log Ω·cm) or more and 13.5 (log Ω·cm) or less, more preferably 9.5 (log Ω·cm) or more and 13.2 (log Ω·cm) or less, and particularly preferably 10.0 (log Ω·cm) or more and 12.5 (log Ω·cm) or less. The volume resistivity of the intermediate transfer belt when a voltage of 500 V is applied for 10 seconds is measured by the following method. A microcurrent meter (Advantest R8430A) is used as the resistance measuring device, and a UR probe (Mitsubishi Chemical Analytech Co., Ltd.) is used as the probe to measure the volume resistivity (log Ω cm) at 6 equally spaced points around the periphery of the intermediate transfer belt, and 3 points at the center and both ends in the width direction, for a total of 18 points, at a voltage of 500 V, application time of 10 seconds, and pressure of 1 kgf, and the average value is calculated. The measurements are also performed in an environment with a temperature of 22°C and a humidity of 55% RH.

[0055] <Method of manufacturing intermediate transfer belt> The method for producing the intermediate transfer belt according to the present embodiment is not particularly limited as long as it is a method capable of producing the intermediate transfer belt so that the outer circumferential surface has the above-mentioned configuration. An example of a method for manufacturing an intermediate transfer belt includes a coating liquid preparation step of preparing a coating liquid containing a resin or a precursor thereof, conductive carbon particles, alkyl silicone oil, and a solvent, a coating film formation step of applying the coating liquid onto the outer periphery of a substrate by a spiral coating method to form a coating film, and a drying step of drying the coating film while increasing the temperature of the substrate. In this method, the intermediate transfer belt according to the present embodiment, which is a single layer, can be obtained. The method for producing the intermediate transfer belt may include other steps in addition to the coating solution preparation step, the coating film formation step, and the drying step, such as a baking step in which the coating film dried in the drying step is baked when a resin precursor is used.

[0056] (Coating solution preparation process) In the coating liquid preparation step, a coating liquid containing a resin or a precursor thereof, conductive carbon particles, alkyl silicone oil, and a solvent is prepared. For example, when the resin is a polyimide resin and the conductive carbon particles are carbon black, a coating liquid is prepared in which, for example, carbon black is dispersed and polyamic acid, which is a precursor of the polyimide resin, and alkyl silicone oil are dissolved in a solvent.

[0057] As a method for preparing the coating liquid, from the viewpoint of pulverizing aggregates of the conductive carbon particles and from the viewpoint of increasing the dispersibility of the conductive carbon particles, it is preferable to carry out a dispersion treatment using a pulverizer such as a ball mill or a jet mill. In addition, in the coating liquid preparation process, from the viewpoint of increasing the dispersibility of the conductive carbon particles, it is preferable to add alkyl silicone oil to the solvent in which the conductive carbon particles are dispersed after performing a dispersion treatment of the conductive carbon particles.

[0058] The solvent is not particularly limited and may be appropriately selected depending on the type of resin used as the resin, etc. For example, when the resin is a polyimide resin or a polyamideimide resin, a polar solvent described below is preferably used as the solvent.

[0059] Examples of polar solvents include N-methyl-2-pyrrolidone (NMP), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N,N-diethylacetamide (DEAc), dimethylsulfoxide (DMSO), hexamethylene phosphoramide (HMPA), N-methylcaprolactam, N-acetyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone (N,N-dimethylimidazolidinone, DMI), and the like. These may be used alone or in combination of two or more.

[0060] (Coating film formation process) In the coating film forming step, the coating liquid is applied onto the outer periphery of the workpiece by a spiral coating method to form a coating film. The material to be coated may be, for example, a cylindrical or columnar metal mold, etc. The material to be coated may be the metal mold whose outer peripheral surface has been treated with a release agent.

[0061] The coating liquid is applied by a spiral coating (flow coating) method. The spiral coating method is carried out, for example, as follows. First, the material to be coated is rotated around its axis with the direction of its rotation axis being horizontal. The coating liquid is discharged from the discharge part of the dispenser onto the outer circumferential surface of the rotating material to coat the outer circumferential surface of the material. At this time, the coating liquid is applied (applied) in a spiral shape to the outer circumferential surface of the material to be coated by moving the discharge part of the dispenser from one end to the other end in the direction of the rotation axis of the rotating material to coat the outer circumferential surface of the material to be coated. Here, by adjusting the coating conditions in the spiral coating method, specifically, the rotation speed of the material to be coated and the movement speed of the dispenser's discharge part, it is possible to control the peak-to-top distance in the cycle of increase and decrease of the amount of silicon on the outer peripheral surface of the intermediate transfer belt.

[0062] (drying process) In the drying step, the coating film formed in the coating film forming step is dried. The drying step removes the solvent contained in the coating film, and a layer is obtained. Examples of methods for drying the coating film include a method of supplying hot air to the coating film and a method of heating the material to be coated.

[0063] (Firing process) As described above, the method for producing the intermediate transfer belt may include a baking step. In the baking step, the coating film dried in the drying step is heated and baked. For example, when the resin is a polyimide resin, the baking step imidizes the polyamic acid contained in the coating film to obtain a polyimide. The heating temperature in the baking step is, for example, in the range of 150° C. to 450° C., and preferably in the range of 200° C. to 430° C. The heating time in the first baking step is, for example, in the range of 20 minutes to 180 minutes, and preferably in the range of 60 minutes to 150 minutes.

[0064] In addition, in the case of a multi-layer intermediate transfer belt, a base layer can be formed on the surface of the material to be coated by a known method, and a surface layer can be formed on the surface of the base layer by the above-mentioned method (a method including a coating liquid preparation process, a coating film formation process, and a drying process), thereby obtaining the intermediate transfer belt of this embodiment. Furthermore, in the case of a multi-layer intermediate transfer belt, a base layer is formed on the surface of the substrate by a known method, and a surface layer containing resin, conductive carbon particles, and alkyl silicone oil is formed on the surface of the base layer by a known method. Thereafter, a portion of the surface layer is removed in the circumferential direction to form a plurality of grooves that are aligned parallel or approximately parallel to the axial direction of the belt, thereby obtaining the intermediate transfer belt according to this embodiment.

[0065] <Transfer device> The transfer device according to this embodiment includes an intermediate transfer belt according to this embodiment, a blade that contacts the outer peripheral surface of the intermediate transfer belt and cleans the outer peripheral surface, a primary transfer device having a primary transfer member that primarily transfers a toner image formed on the surface of an image carrier to the outer peripheral surface of the intermediate transfer belt, and a secondary transfer device that is arranged in contact with the outer peripheral surface of the intermediate transfer belt and has a secondary transfer member that secondarily transfers the toner image transferred to the outer peripheral surface of the intermediate transfer belt to the surface of a recording medium.

[0066] 〔blade〕 The blade comes into contact with the outer peripheral surface of the intermediate transfer belt and cleans the outer peripheral surface. The blade cleans the toner (also called residual toner) remaining on the outer peripheral surface of the intermediate transfer belt after the toner image transferred onto the outer peripheral surface of the intermediate transfer belt is secondarily transferred onto the surface of a recording medium. The blade is used while being supported by, for example, a rigid plate-like support member.

[0067] The blade may be any known blade used for cleaning the intermediate transfer belt, and is preferably made of rubber such as polyurethane rubber.

[0068] Here, the contact conditions of the blade with the intermediate transfer belt will be described with reference to FIG. 1 is a schematic diagram for explaining the contact conditions between the intermediate transfer belt and the blade, in which BE denotes the intermediate transfer belt, CB denotes the blade, and CBS denotes a support member that supports the blade.

[0069] As shown in FIG. 1, the pressing force NF with which the blade CB is pressed against the intermediate transfer belt BE is preferably 1 N·m to 6 N·m, more preferably 1.5 N·m to 5 N·m, from the viewpoint of obtaining good cleaning performance. The amount of penetration d of the blade CB into the intermediate transfer belt BE is preferably 0.5 mm or more and 2.0 mm or less, and more preferably 0.6 mm or more and 1.8 mm or less. Furthermore, the angle WA (Working Angle) at the contact portion between the intermediate transfer belt BE and the blade CB is preferably 5° or more and 30° or less, and more preferably 10° or more and 20° or less.

[0070] Here, the blade pressing force NF is calculated using the following formula. Formula: Pressing force NF=k×d In the formula, k is the spring constant specific to the blade, and d is the amount of penetration of the blade into the intermediate transfer belt (see FIG. 1). The blade-specific spring constant k is obtained by applying a displacement to the cleaning blade and measuring the load with a load cell. The amount of penetration d of the blade into the belt is found by calculating the amount of displacement of the intermediate transfer belt when the blade fixed to the supporting member is brought into contact with the intermediate transfer belt.

[0071] [Primary transfer device] The primary transfer device has a metallic primary transfer roll that is in contact with the inner surface of the intermediate transfer belt and applies an electric field to the intermediate transfer belt, and is a device that performs primary transfer of a toner image formed on the surface of an image carrier onto the outer surface of the intermediate transfer belt. The metallic primary transfer roll is disposed opposite to the image carrier with the intermediate transfer belt sandwiched therebetween. In the primary transfer device, the metallic primary transfer roll applies a voltage of the opposite polarity to the charge polarity of the toner to the intermediate transfer belt, thereby performing primary transfer of the toner image onto the outer peripheral surface of the intermediate transfer belt. Examples of the primary transfer roll include metal members such as iron, copper, brass, stainless steel (SUS), sulfur composite steel (SUM), aluminum, nickel, etc. The primary transfer roll may be a hollow metal roll or a solid metal roll. The outer diameter of the primary transfer roll is, for example, in the range of 4 mm or more and 28 mm or less. The circumferential width of the nip region where the intermediate transfer belt is sandwiched between the primary transfer roll and the image carrier is, for example, in the range of 0.5 mm or more and 5 mm or less.

[0072] [Secondary Transfer Device] The secondary transfer device is a device that performs second transfer of the toner image transferred onto the outer peripheral surface of the intermediate transfer belt onto the surface of a recording medium. The secondary transfer device includes, for example, a secondary transfer roll disposed on the outer peripheral surface side of the intermediate transfer belt, i.e., the side on which the toner image is held, and a back roll disposed on the inner peripheral surface side of the intermediate transfer belt, i.e., the side opposite the side on which the toner image is held. In the secondary transfer device, the intermediate transfer belt and the recording medium are sandwiched between the secondary transfer roll and the back roll to form a transfer electric field, whereby the toner image on the intermediate transfer belt is secondarily transferred to the recording medium.

[0073] <Image forming device> The image forming apparatus according to this embodiment includes an image carrier, a charging device that charges the surface of the image carrier, an electrostatic latent image forming device that forms an electrostatic latent image on the charged surface of the image carrier, a developing device that contains a developer including toner and uses the developer to develop the electrostatic latent image formed on the surface of the image carrier to form a toner image, and a transfer device according to this embodiment described above.

[0074] The image forming apparatus according to the present embodiment may be any of known image forming apparatuses, such as an apparatus equipped with a fixing means for fixing a toner image transferred onto the surface of a recording medium; an apparatus equipped with a cleaning means for cleaning the surface of an image holder before charging after the toner image is transferred; an apparatus equipped with a discharging means for irradiating the surface of the image holder with discharging light to discharge the surface before charging after the toner image is transferred; and an apparatus equipped with an image holder heating member for increasing the temperature of the image holder and reducing the relative temperature.

[0075] In the image forming apparatus according to the present embodiment, for example, the portion including the image carrier may have a cartridge structure (process cartridge) that is detachably attached to the image forming apparatus.

[0076] Hereinafter, an example of an image forming apparatus according to the present embodiment will be described with reference to the drawings. However, the image forming apparatus according to the present embodiment is not limited to this. Note that only the main parts shown in the drawings will be described, and the description of the rest will be omitted.

[0077] FIG. 2 is a schematic diagram showing the configuration of the image forming apparatus according to the present embodiment.

[0078] As shown in Fig. 2, the image forming apparatus 100 according to the present embodiment is, for example, an intermediate transfer type image forming apparatus generally called a tandem type, and includes a plurality of image forming units 1Y, 1M, 1C, and 1K (an example of a toner image forming apparatus) in which toner images of each color component are formed by an electrophotographic method, a primary transfer section 10 that sequentially transfers (primary transfer) each of the color component toner images formed by each of the image forming units 1Y, 1M, 1C, and 1K to an intermediate transfer belt 15, a secondary transfer section 20 that collectively transfers (secondary transfer) the superimposed toner images transferred onto the intermediate transfer belt 15 to a recording medium, paper K, and a fixing device 60 that fixes the secondary transferred image onto the paper K. The image forming apparatus 100 also includes a control section 40 that controls the operation of each device (each section). Here, the intermediate transfer belt according to the present embodiment is applied as the intermediate transfer belt 15.

[0079] Each of the image forming units 1Y, 1M, 1C, and 1K of the image forming apparatus 100 includes a photoconductor 11 that rotates in the direction of arrow A and holds a toner image formed on its surface.

[0080] Around the photoconductor 11, there is provided a charger 12 as an example of a charging device that charges the photoconductor 11, and there is provided a laser exposure device 13 (the exposure beam is indicated by the symbol Bm in the figure) as an example of an electrostatic latent image forming device that writes an electrostatic latent image on the photoconductor 11.

[0081] In addition, around the photoconductor 11, there is provided a developing device 14 as an example of a developing device, which contains toner of each color component and makes the electrostatic latent image on the photoconductor 11 visible using the toner, and there is provided a primary transfer roll 16 which transfers the toner image of each color component formed on the photoconductor 11 to an intermediate transfer belt 15 at the primary transfer section 10.

[0082] Furthermore, a photoreceptor cleaner 17 that removes residual toner on the photoreceptor 11 is provided around the photoreceptor 11, and electrophotographic devices including a charger 12, a laser exposure device 13, a developer 14, a primary transfer roll 16, and the photoreceptor cleaner 17 are sequentially arranged along the rotation direction of the photoreceptor 11. These image forming units 1Y, 1M, 1C, and 1K are arranged in a substantially linear fashion in the order of yellow (Y), magenta (M), cyan (C), and black (K) from the upstream side of the intermediate transfer belt 15.

[0083] The intermediate transfer belt 15 is driven (rotated) in a circular manner by various rolls at a speed suited to the purpose in the direction B shown in Fig. 2. The various rolls include a drive roll 31 driven by a motor (not shown) excellent in constant speed performance to rotate the intermediate transfer belt 15, a support roll 32 supporting the intermediate transfer belt 15 extending in a substantially straight line along the arrangement direction of the photoconductors 11, a tensioning roll 33 that applies tension to the intermediate transfer belt 15 and functions as a correction roll to prevent the intermediate transfer belt 15 from meandering, a back roll 25 provided in the secondary transfer section 20, and a cleaning back roll 34 provided opposite an intermediate transfer belt cleaning blade 35 that comes into contact with the outer circumferential surface of the intermediate transfer belt 15 and cleans the outer circumferential surface.

[0084] The primary transfer section 10 is composed of a primary transfer roll 16 arranged opposite the photoconductor 11 with the intermediate transfer belt 15 sandwiched therebetween. The primary transfer roll 16 is arranged in pressure contact with the photoconductor 11 with the intermediate transfer belt 15 sandwiched therebetween, and a voltage (primary transfer bias) of the opposite polarity to the charge polarity of the toner (negative polarity; the same applies below) is applied to the primary transfer roll 16. As a result, the toner images on the photoconductors 11 are electrostatically attracted to the intermediate transfer belt 15 in sequence, and superimposed toner images are formed on the intermediate transfer belt 15.

[0085] The secondary transfer unit 20 includes a back roll 25 and a secondary transfer roll 22 that is disposed on the toner image bearing surface side of the intermediate transfer belt 15 .

[0086] The back roll 25 has a surface resistivity of 1×10 7 Ω / □ or more 1×10 10 The hardness is set to, for example, 70° (Asker C: manufactured by Kobunshi Keiki Co., Ltd., the same applies below.) The back roll 25 is disposed on the back side of the intermediate transfer belt 15 to constitute an opposing electrode of the secondary transfer roll 22, and is in contact with a metallic power supply roll 26 to which a secondary transfer bias is stably applied.

[0087] On the other hand, the secondary transfer roll 22 has a volume resistivity of 10 7.5 Ωcm or more 10 8.5 The secondary transfer roll 22 is a cylindrical roll of Ωcm or less. The secondary transfer roll 22 is arranged in pressure contact with the back roll 25 with the intermediate transfer belt 15 sandwiched therebetween, and the secondary transfer roll 22 is further grounded to form a secondary transfer bias between the secondary transfer roll 22 and the back roll 25, and performs a second transfer of the toner image onto the paper K transported to the secondary transfer unit 20.

[0088] In addition, downstream of the secondary transfer section 20 of the intermediate transfer belt 15, a cleaning blade 35 for the intermediate transfer belt is provided in a freely detachable manner to remove residual toner and paper dust on the intermediate transfer belt 15 after the secondary transfer and to clean the outer peripheral surface of the intermediate transfer belt 15. Further, a secondary transfer roll cleaning member 22A is provided downstream of the secondary transfer section 20 of the secondary transfer roll 22 to remove residual toner and paper powder on the secondary transfer roll 22 after secondary transfer and clean the outer circumferential surface of the intermediate transfer belt 15. The secondary transfer roll cleaning member 22A is exemplified by a cleaning blade, but may also be a cleaning roll. The image forming apparatus 100 may be configured to include a secondary transfer belt (an example of a secondary transfer member) instead of the secondary transfer roll 22.

[0089] Meanwhile, a reference sensor (home position sensor) 42 is provided upstream of the yellow image forming unit 1Y to generate a reference signal that serves as a reference for timing image formation in each of the image forming units 1Y, 1M, 1C, and 1K. An image density sensor 43 for adjusting image quality is provided downstream of the black image forming unit 1K. This reference sensor 42 generates a reference signal by recognizing a mark provided on the back side of the intermediate transfer belt 15, and each of the image forming units 1Y, 1M, 1C, and 1K is configured to start image formation in response to an instruction from the control unit 40 based on the recognition of this reference signal.

[0090] Furthermore, in the image forming apparatus according to this embodiment, as transport means for transporting the paper K, there are provided a paper storage section 50 for storing the paper K, a paper feed roll 51 for taking out and transporting the paper K accumulated in the paper storage section 50 at a predetermined timing, a transport roll 52 for transporting the paper K fed by the paper feed roll 51, a transport guide 53 for sending the paper K transported by the transport roll 52 to the secondary transfer section 20, a transport belt 55 for transporting the paper K transported after secondary transfer by the secondary transfer roll 22 to the fixing device 60, and a fixing entrance guide 56 for guiding the paper K to the fixing device 60.

[0091] Next, a basic image forming process of the image forming apparatus according to this embodiment will be described using the image forming apparatus shown in FIG. In the image forming apparatus of this embodiment, image data output from an image reading device (not shown) or a personal computer (PC) (not shown), etc., is subjected to image processing by an image processing device (not shown), and then image formation is performed by image forming units 1Y, 1M, 1C, and 1K.

[0092] The image processing device performs image processing on the input reflectance data, such as shading correction, positional deviation correction, brightness / color space conversion, gamma correction, and various image editing such as frame erasure, color editing, and movement editing. The image data that has undergone image processing is converted into color material gradation data of four colors, Y, M, C, and K, and is output to the laser exposure device 13.

[0093] In the laser exposure device 13, an exposure beam Bm emitted from, for example, a semiconductor laser is irradiated onto the photoconductor 11 of each of the image forming units 1Y, 1M, 1C, and 1K in accordance with the input color material gradation data. In each of the photoconductors 11 of the image forming units 1Y, 1M, 1C, and 1K, the surface is charged by the charger 12, and then the surface is scanned and exposed by the laser exposure device 13 to form an electrostatic latent image. The formed electrostatic latent image is developed into a toner image of each color of Y, M, C, and K by each of the image forming units 1Y, 1M, 1C, and 1K.

[0094] The toner images formed on the photoconductors 11 of the image forming units 1Y, 1M, 1C, and 1K are transferred onto the intermediate transfer belt 15 in the primary transfer section 10 where each photoconductor 11 comes into contact with the intermediate transfer belt 15. More specifically, in the primary transfer section 10, a voltage (primary transfer bias) of the opposite polarity to the charging polarity (negative polarity) of the toner is applied to the base material of the intermediate transfer belt 15 by the primary transfer roll 16, and the toner images are sequentially superimposed on the outer circumferential surface of the intermediate transfer belt 15 to perform the primary transfer.

[0095] After the toner images are sequentially primarily transferred onto the outer peripheral surface of the intermediate transfer belt 15, the intermediate transfer belt 15 moves to transport the toner images to the secondary transfer unit 20. When the toner images are transported to the secondary transfer unit 20, the transport means rotates the paper feed roll 51 in accordance with the timing at which the toner images are transported to the secondary transfer unit 20, and paper K of the desired size is supplied from the paper storage unit 50. The paper K supplied by the paper feed roll 51 is transported by the transport roll 52 and reaches the secondary transfer unit 20 via the transport guide 53. Before reaching the secondary transfer unit 20, the paper K is temporarily stopped, and a positioning roll (not shown) rotates in accordance with the movement timing of the intermediate transfer belt 15 on which the toner images are held, thereby aligning the position of the paper K with the position of the toner image.

[0096] In the secondary transfer section 20, the secondary transfer roll 22 is pressed against the back roll 25 via the intermediate transfer belt 15. At this time, the paper K, which has been transported in time, is sandwiched between the intermediate transfer belt 15 and the secondary transfer roll 22. At this time, when a voltage (secondary transfer bias) of the same polarity as the charging polarity (negative polarity) of the toner is applied from the power supply roll 26, a transfer electric field is formed between the secondary transfer roll 22 and the back roll 25. Then, the unfixed toner images held on the intermediate transfer belt 15 are electrostatically transferred collectively onto the paper K in the secondary transfer section 20, which is pressed by the secondary transfer roll 22 and the back roll 25.

[0097] Thereafter, the paper K onto which the toner image has been electrostatically transferred is transported as it is after being peeled off from the intermediate transfer belt 15 by the secondary transfer roll 22, and is transported to a transport belt 55 provided downstream of the secondary transfer roll 22 in the paper transport direction. The transport belt 55 transports the paper K to the fixing device 60 at an optimal transport speed for the fixing device 60. The unfixed toner image on the paper K transported to the fixing device 60 is fixed onto the paper K by being subjected to a fixing process using heat and pressure by the fixing device 60. The paper K on which the fixed image has been formed is then transported to an ejected paper storage section (not shown) provided in the ejection section of the image forming apparatus.

[0098] On the other hand, after the transfer to the paper K is completed, residual toner, etc. remaining on the intermediate transfer belt 15 is transported to the intermediate transfer belt cleaning blade 35 as the intermediate transfer belt 15 rotates, and is removed from the intermediate transfer belt 15 by the intermediate transfer belt cleaning blade 35.

[0099] Although the present embodiment has been described above, the present invention is not limited to the above embodiment, and various modifications, changes, and improvements are possible. EXAMPLES

[0100] Hereinafter, examples of the present invention will be described, but the present invention is not limited to the following examples. In the following description, unless otherwise specified, all "parts" and "%" are based on mass.

[0101] [Example 1] <Preparation of Coating Solution A> 1000g of fully aromatic polyimide varnish (solid content: 18% by mass, manufactured by Unitika, U-imide KX, solvent: NMP) was mixed with 39.6g (22phr) of oxidized gas black (Channel Black, manufactured by Orion Engineered Carbons, FW200, number average primary particle size: 13nm) as conductive carbon particles, and the mixture was passed through a φ0.1mm orifice at a pressure of 200MPa using a high-pressure collision type disperser (manufactured by Genus), and the slurry was collided into two parts 20 times to obtain a dispersion. The resulting dispersion was mixed with polyether-modified dimethyl silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KP-126, viscosity at 25°C: 10mm) as alkyl silicone oil. 2 / s) was added and stirred to obtain coating solution A.

[0102] <Production of Belt A1> -Preparing the material to be coated- A cylindrical mold made of stainless steel having an outer diameter of 278 mm and a length of 400 mm was prepared, and a silicone-based mold release agent (manufactured by Shin-Etsu Chemical Co., Ltd., product name: Sepacoat SP) was applied to its outer surface, followed by a drying treatment (mold release agent treatment). The cylindrical mold treated with a mold release agent was used as the material to be coated.

[0103] - Formation of coating film - While rotating a cylindrical mold (coated material) treated with a release agent in the circumferential direction at a speed of 42 rpm, the above-mentioned coating liquid A was discharged from a dispenser with a diameter of 1.0 mm from the end of the cylindrical mold, and coating was performed by pressing with a uniform pressure using a metal blade installed on the mold. The dispenser unit was moved in the axial direction of the cylindrical mold at a speed of 200 mm / min, whereby the coating liquid A1 was applied in a spiral shape onto the cylindrical mold, forming a coating film.

[0104] - Drying of the coating film - Thereafter, the mold and the coating film were dried in a drying oven at 140° C. in an air atmosphere for 15 minutes while rotating at 10 rpm. After drying, the solvent evaporated from the coating film, and the coating film was transformed into a polyamic acid resin molded article having self-supporting properties.

[0105] - Firing - Next, the polyamic acid resin molded product was placed in an oven at an ultimate temperature of 320° C. for 4 hours to obtain a single-layer type intermediate transfer belt A1. The intermediate transfer belt A1 had a film thickness of 80 μm.

[0106] [Examples 2 to 7] Intermediate transfer belts A2 to A7 were obtained in the same manner as in Example 1, except that the rotation speed of the cylindrical mold and the movement speed of the dispenser were changed as shown in Table 1 below when forming the coating film.

[0107] [Example 8] An intermediate transfer belt B1 was obtained in the same manner as in Example 1, except that a coating solution B was used in which the amount of alkyl silicone oil in the coating solution A was changed to 3.0 g.

[0108] [Example 9] The alkyl silicone oil in the coating solution A was replaced with polyether-modified dimethyl silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KP-109, viscosity at 25°C: 10 mm 2 An intermediate transfer belt C1 was obtained in the same manner as in Example 1, except that the coating solution C1 was changed to the coating solution C2 (1 / s).

[0109] [Example 10] The alkyl silicone oil in the coating solution A was replaced with dimethyl silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KF-96, viscosity at 25°C: 10 mm 2 An intermediate transfer belt C2 was obtained in the same manner as in Example 1, except that the coating solution C2 was changed to the coating solution C1 having the same composition as in Example 1.

[0110] [Comparative Example 1] An intermediate transfer belt installed in an Apeos C8180 (manufactured by FUJIFILM Business Innovation Co., Ltd.) was taken out, cut out into a shape that could be attached to an Apeos C7070, and processed to obtain an intermediate transfer belt C1.

[0111] [Comparative Examples 2 to 3] Intermediate transfer belts C2 to C3 were obtained in the same manner as in Example 1, except that the rotation speed of the cylindrical mold and the movement speed of the dispenser were changed as shown in Table 1 below when forming the coating film.

[0112] [Measurement of intermediate transfer belt] For each of the obtained intermediate transfer belts, the silicon amount (atomic %) was measured along the axial direction of the outer peripheral surface by X-ray photoelectron spectroscopy using the method described above. This allowed us to determine whether the silicon amount increased or decreased periodically along the axial direction, the distance between the peak tops in the cycle of increase or decrease in the silicon amount, and the difference between the peak top and the peak bottom in the cycle of increase or decrease in the silicon amount. Furthermore, the difference between the surface resistivity at the peak top and the surface resistivity at the peak bottom in the cycle of increase and decrease of the silicon amount was determined by the method already described. The results are shown in Table 1. In Table 1, if the amount of silicon increases or decreases periodically along the axial direction, it is indicated as "Y", and if the amount of silicon does not increase or decrease periodically along the axial direction, it is indicated as "N".

[0113] [Manufacture of transfer devices and image forming devices] The intermediate transfer belt obtained in each example and the blade described below were attached to the inside of a transfer device of Apeos C7070 (manufactured by Fujifilm Business Innovation Co., Ltd.), thereby obtaining an image forming apparatus equipped with a transfer device. The blade used was a rubber blade made of polyurethane rubber with a free length of 8.0 mm, a width of 334 mm, and a thickness of 1.9 mm attached to a metal holder. As for the contact conditions between the intermediate transfer belt and the blade, the pressing force NF (Normal Force) was set to 2.7 gf / mm, and the angle W / A was set to 18°. Then, the following evaluations were carried out using this image forming apparatus.

[0114] [evaluation] (1. Evaluation of blade curl) Using the obtained image forming apparatus, 1000 sheets of A4 size white paper were continuously printed in an atmosphere of 28° C. and 85% RH, and the blade curl was evaluated. -Evaluation criteria- G1: No blade curling occurred G2: Blade curl causes streaks on the print G3: The image forming device stops intermittently during continuous printing due to blade curling. G4: Printing is not possible due to blade curling.

[0115] (2. Evaluation of transfer efficiency) Using the obtained image forming device, a 100% solid black band chart image was output, and a hard stop was performed during the secondary transfer process. The toner weight a on the outer surface of the intermediate transfer belt (toner weight before secondary transfer) was measured, and the toner weight b transferred onto the paper was also measured, and the transfer efficiency was calculated using the following formula. Transfer efficiency [%] = b / a × 100 -Evaluation criteria- G1: Transfer efficiency is 95% or more. G2: Transfer efficiency is 90% or more but less than 95%. G3: Transfer efficiency is less than 90%.

[0116] (3. Evaluation of cleaning ability) Using the obtained image forming device, 1,000 sheets of a full-grid chart equivalent to 1% density were printed on A4-sized plain paper in an ambient environment of 28°C and 85% RH, and then a 100% solid, untransferred sheet was inserted into the contact area between the intermediate transfer belt and the blade, and the degree of streak-like cleaning defects was evaluated. -Evaluation criteria- G1: No cleaning failure has occurred. G2: Cleaning defects are not visible G3: Cleaning defects are clearly visible. [Table 1]

[0117] From the results shown in Table 1, it is understood that the intermediate transfer belt of this embodiment suppresses the curling of the blade.

[0118] Preferred aspects and effects of the present disclosure will be described below. (((1))) A conductive material comprising a resin, conductive carbon particles, and an alkyl silicone oil or a modified alkyl silicone oil; On the outer circumferential surface, there are formed regions having different contents of the alkyl silicone oil and its modified product, When the amount of silicon (atomic %) on the outer peripheral surface is measured along the axial direction using X-ray photoelectron spectroscopy, the amount of silicon periodically increases and decreases along the axial direction, and the distance between the peak tops in the period of increase and decrease in the amount of silicon is 0.1 mm or more and 5.0 mm or less. (((2))) The intermediate transfer belt according to (((1))), wherein the peak top distance is 0.1 mm or more and 3.0 mm or less. (((3))) The intermediate transfer belt according to (((1))) or (((2))), wherein a difference between a peak top and a peak bottom in the cycle of increase and decrease of the silicon amount is 0.1 Atomic % or more and 5.0 Atomic % or less. (((4))) The intermediate transfer belt according to (((1))), wherein the peak-to-peak distance is 0.1 mm or more and 3.0 mm or less, and the difference between the peak top and the peak bottom in the increase / decrease cycle of the silicon amount is 0.1 Atomic % or more and 5.0 Atomic % or less. (((5))) The intermediate transfer belt according to any one of (((1))) to (((4))), wherein the difference between the surface resistivity at the peak top portion and the surface resistivity at the peak bottom portion in the cycle of increase and decrease of the silicon amount is 0.03 log Ω / □ or less. (((6))) The intermediate transfer belt according to (((5))), wherein the difference between the surface resistivity at a peak top portion and the surface resistivity at a peak bottom portion in the cycle of increase and decrease of the silicon amount is 0.02 log Ω / □ or less.

[0119] (((7))) An intermediate transfer belt according to any one of (((1))) to (((6))); a blade that comes into contact with an outer peripheral surface of the intermediate transfer belt and cleans the outer peripheral surface; a primary transfer device having a primary transfer member for primarily transferring a toner image formed on a surface of an image carrier onto an outer peripheral surface of the intermediate transfer belt; a secondary transfer device that is disposed in contact with an outer peripheral surface of the intermediate transfer belt and has a secondary transfer member that secondarily transfers the toner image transferred onto the outer peripheral surface of the intermediate transfer belt onto a surface of a recording medium; A transfer device comprising: (((8))) an image carrier; and a charging device for charging the surface of the image carrier; an electrostatic latent image forming device for forming an electrostatic latent image on a charged surface of the image carrier; a developing device that contains a developer containing a toner and develops an electrostatic latent image formed on the surface of the image carrier with the developer to form a toner image; A transfer device according to (((7))) that transfers the toner image onto a surface of a recording medium; An image forming apparatus comprising:

[0120] According to the invention pertaining to (((1))), there is provided an intermediate transfer belt which includes a resin, conductive carbon particles, and an alkyl silicone oil and a modified product thereof, and on its outer circumferential surface, there are formed regions with different contents of the alkyl silicone oil and the modified product thereof, and when the silicon amount (atomic %) of the outer circumferential surface is measured along the axial direction using X-ray photoelectron spectroscopy, the silicon amount increases and decreases periodically along the axial direction, and the distance between the peak tops in the cycle of increase and decrease in the silicon amount is less than 0.1 mm or more than 5.0 mm, which can suppress curling of a blade which comes into contact with the outer circumferential surface of the intermediate transfer belt to clean the outer circumferential surface of the intermediate transfer belt.

[0121] According to the invention related to (((2))) or (((4))), an intermediate transfer belt is provided that can suppress curling of a blade that comes into contact with the outer peripheral surface of the intermediate transfer belt to clean the outer peripheral surface, compared to when the peak-to-top distance is more than 3.0 and 5.0 mm or less. According to the invention related to (((3))) or (((4))), an intermediate transfer belt is provided that can suppress curling of a blade that comes into contact with the outer peripheral surface of the intermediate transfer belt to clean the outer peripheral surface, compared to when the difference between the peak top and the peak bottom in the cycle of increase and decrease in silicon amount is less than 0.1 Atomic % or exceeds 5.0 Atomic %. According to the invention related to (((5))), an intermediate transfer belt is provided that can suppress curling of a blade that comes into contact with the outer peripheral surface of the intermediate transfer belt to clean the outer peripheral surface, compared to when the difference between the surface resistivity at the peak top portion and the surface resistivity at the peak bottom portion exceeds 0.03 log Ω / □. According to the invention related to (((6))), an intermediate transfer belt is provided that can suppress curling of a blade that comes into contact with the outer peripheral surface of the intermediate transfer belt to clean the outer peripheral surface, compared to when the difference between the surface resistivity at the peak top portion and the surface resistivity at the peak bottom portion is greater than 0.02 log Ω / □ and is 0.03 log Ω / □ or less.

[0122] According to the invention related to (((7))) or (((8))), there is provided a transfer device or image forming apparatus which can suppress curling of a blade which comes into contact with the outer peripheral surface of an intermediate transfer belt to clean the outer peripheral surface, compared to a case in which the intermediate transfer belt includes a resin, conductive carbon particles, and an alkyl silicone oil and a modified product thereof, and on the outer peripheral surface, regions having different contents of the alkyl silicone oil and the modified product thereof are formed, and when the silicon amount (atomic %) of the outer peripheral surface is measured along the axial direction using X-ray photoelectron spectroscopy, the silicon amount increases and decreases periodically along the axial direction, and the distance between the peak tops in the cycle of increase and decrease of the silicon amount is less than 0.1 mm or more than 5.0 mm. [Explanation of symbols]

[0123] 1Y, 1M, 1C, 1K Image forming unit 10 Primary transfer section 11 Photoreceptor 12 Charger 13 Laser exposure device 14 Developer 15 Intermediate transfer belt 16 Primary transfer roll 17 Photoconductor cleaner 20 Secondary transfer section 22 Secondary transfer roll 22A Secondary transfer roll cleaning member 25 Back roll 26 Power supply roll 31 Driving Roll 32 Support roll 33 Tensioning roll 34 Cleaning back roll 35 Intermediate transfer belt cleaning blade 40 Control section 42 Reference Sensor 43 Image density sensor 50 Paper storage section 51 Paper feed roll 52 Transport roll 53 Transport guide 55 Conveyor belt 56 Fixing entrance guide 60 Fixing device 100 Image forming device K Paper

Claims

1. The conductive material includes a resin, conductive carbon particles, and an alkyl silicone oil or a modified product thereof, On the outer peripheral surface, regions having different contents of the alkyl silicone oil and its modified product are formed, When the amount of silicon (atomic %) on the outer peripheral surface is measured along the axial direction using X-ray photoelectron spectroscopy, the amount of silicon increases and decreases periodically along the axial direction, and the distance between peak tops in the period of increase and decrease in the amount of silicon is 0.1 mm or more and 5.0 mm or less.

2. 2. The intermediate transfer belt according to claim 1, wherein the peak-to-peak distance is 0.1 mm or more and 3.0 mm or less.

3. 2. The intermediate transfer belt according to claim 1, wherein a difference between a peak top and a peak bottom in the cycle of increase and decrease of the silicon amount is 0.1 Atomic % or more and 5.0 Atomic % or less.

4. 2. The intermediate transfer belt according to claim 1, wherein the peak-to-top distance is from 0.1 mm to 3.0 mm, and the difference between the peak top and the peak bottom in the cycle of increase and decrease of the silicon amount is from 0.1 Atomic % to 5.0 Atomic %.

5. 2. The intermediate transfer belt according to claim 1, wherein a difference between the surface resistivity at a peak top portion and the surface resistivity at a peak bottom portion in the cycle of increasing and decreasing the amount of silicon is 0.03 log Ω / □ or less.

6. 6. The intermediate transfer belt according to claim 5, wherein a difference between the surface resistivity at a peak top portion and the surface resistivity at a peak bottom portion in the cycle of increase and decrease of the silicon amount is 0.02 log Ω / □ or less.

7. An intermediate transfer belt according to any one of claims 1 to 6, a blade that comes into contact with an outer peripheral surface of the intermediate transfer belt and cleans the outer peripheral surface; a primary transfer device having a primary transfer member for primarily transferring a toner image formed on a surface of an image carrier onto an outer peripheral surface of the intermediate transfer belt; a secondary transfer device that is disposed in contact with an outer peripheral surface of the intermediate transfer belt and has a secondary transfer member that secondarily transfers the toner image transferred onto the outer peripheral surface of the intermediate transfer belt onto a surface of a recording medium; A transfer device comprising:

8. An image carrier; a charging device for charging the surface of the image carrier; an electrostatic latent image forming device for forming an electrostatic latent image on a charged surface of the image carrier; a developing device that contains a developer including a toner and develops an electrostatic latent image formed on the surface of the image carrier with the developer to form a toner image; A transfer device according to claim 7 for transferring the toner image onto a surface of a recording medium; An image forming apparatus comprising:

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