Transfer unit, transfer device, and image forming apparatus

Abstract

The present invention provides a transfer unit, a transfer device, and an image forming apparatus. The transfer unit includes: an intermediate transfer belt as an endless belt, which is an endless belt containing a resin and conductive carbon particles, and the conductive carbon particles present in an evaluation area of 6.3 μm × 4.2 μm on the outer peripheral surface satisfy a specific spatial distribution; and a cleaning mechanism having a cleaning blade that cleans the outer peripheral surface of the intermediate transfer belt, and the cleaning blade is a cleaning blade that contacts the outer peripheral surface of the intermediate transfer belt. When the 100% modulus of elasticity at a specified elongation of the contact portion of the cleaning blade with the intermediate transfer belt is M100 (MPa) and the resilience modulus of elasticity of the contact portion is Re (%), the value of M100 / Re is 0.25 or more and the value of Re is 25 or more.

Description

Technical Field

[0001] The present invention relates to a transfer unit, a transfer device, and an image forming device. Background Art

[0002] In an image forming device (such as a copying machine, a facsimile machine, a printer, etc.) using an electrophotographic method, a toner image formed on the surface of an image holding body is transferred to the surface of a recording medium, and fixed on the recording medium to form an image. It should be noted that in such a transfer of a toner image to a recording medium, for example, a conductive endless belt such as an intermediate transfer belt is used.

[0003] For example, Japanese Patent Application Laid-Open No. 2007-011117 discloses "an intermediate transfer belt having at least a surface layer on a substrate, characterized in that the surface layer contains an aggregate of conductive particles having an average particle diameter of 0.5 to 25 μm".

[0004] Japanese Patent Application Laid-Open No. 2007-078789 discloses "an intermediate transfer belt having at least a surface layer on a substrate, characterized in that the surface layer contains resin fine particles coated with a metal". Summary of the Invention

[0005] Technical Problem to be Solved by the Invention

[0006] In an image forming device using an endless belt as an intermediate transfer belt, when using a recording medium having large surface irregularities such as embossed paper (hereinafter also referred to as "irregular paper"), when transferring a toner image from the intermediate transfer belt to the recording medium, the intermediate transfer belt cannot follow the irregularities of the recording medium, the transferability is reduced, and image blanking may occur. Therefore, it is required to maintain an excellent state of transferability to the irregular paper even if the intermediate transfer belt cannot follow the irregularities of the recording medium.

[0007] The technical problem to be solved by the present invention is to provide a transfer unit that has excellent transfer maintainability to embossed paper as compared with a case where the integral value of the statistic L(r) in the intermediate transfer belt is less than 0.1 and the value of M100 / Re in the cleaning blade is less than 0.25, or a case where the integral value of the statistic L(r) in the intermediate transfer belt is less than 0.1 and the value of Re in the cleaning blade is less than 25.

[0008] Means for Solving the Technical Problem

[0009] The above technical problem is solved by the following solution.

[0010] According to a first aspect of the present invention, there is provided a transfer unit including:

[0011] The intermediate transfer belt as a toroidal belt is a toroidal belt containing a resin and conductive carbon particles. In the spatial distribution of the conductive carbon particles present in an evaluation region of 6.3 μm × 4.2 μm on the outer peripheral surface, the integral value of the statistic L(r) represented by the following formula (1) where the inter-particle distance r is 0.05 μm or more and 0.30 μm or less is 0 or more and 0.1 or less, and

[0012] A cleaning mechanism having a cleaning blade that sweeps the outer peripheral surface of the intermediate transfer belt. The cleaning blade is a cleaning blade that contacts the outer peripheral surface of the intermediate transfer belt. When the 100% modulus of elasticity at a specified elongation M100 (MPa) of the contact portion of the cleaning blade with the intermediate transfer belt and the resilience modulus of elasticity Re (%) of the contact portion are set, the value of M100 / Re is 0.25 or more and the value of Re is 25 or more.

[0013] [Equation 1]

[0014]

[0015] In the above formula (1), r represents the inter-particle distance, and K(r) represents Ripley's K function K(r) represented by the following formula (2).

[0016] [Equation 2]

[0017]

[0018] In the above formula (2), 1(|X i −X j |≤r) represents an indicator function, X i and X j represent the coordinates of point i and point j respectively, |X i −X j | represents the Euclidean distance between the coordinate X i and the coordinate X j r represents the inter-particle distance, s(|X i −X j |) represents the edge correction coefficient s(x) of the evaluation region represented by the following formula (3), x = |X i −X j |, N represents the total number of particles in the evaluation region, and λ represents the number density of particles in the evaluation region.

[0019] [Equation 3]

[0020]

[0021] In the above formula (3), L x and L yrespectively represent the lengths (μm) of the sides in the x-axis direction and y-axis direction of the evaluation region, x = |X i −X j |, X i and X j respectively represent the coordinates of point i and point j, |X i −X j | represents the Euclidean distance between coordinate Xi and coordinate Xj.

[0022] According to the second aspect of the present invention, the above resin contains at least one selected from the group consisting of polyimide resin, polyamideimide resin, aromatic polyetheretherketone resin, polyphenylene sulfide resin, and polyetherimide resin.

[0023] According to the third aspect of the present invention, the above resin contains polyimide resin.

[0024] According to the fourth aspect of the present invention, the number average primary particle diameter of the above conductive carbon particles is 10 nm or more and 20 nm or less.

[0025] According to the fifth aspect of the present invention, the number average primary particle diameter of the above conductive carbon particles is 10 nm or more and 15 nm or less.

[0026] According to the sixth aspect of the present invention, the above conductive carbon particles are channel black.

[0027] According to the seventh aspect of the present invention, the contact pressure of the above cleaning blade with respect to the above intermediate transfer belt is 1.0 gf / mm or more and 4.0 gf / mm or less.

[0028] According to the eighth aspect of the present invention, there is provided a transfer device, which includes: the above transfer unit; a primary transfer mechanism that transfers the toner image formed on the surface of the image holding body to the surface of the above intermediate transfer belt of the above transfer unit at one time; and a secondary transfer mechanism that transfers the toner image transferred to the surface of the above intermediate transfer belt to the surface of the recording medium at two times.

[0029] According to the ninth aspect of the present invention, there is provided an image forming apparatus, which includes: an image holding body; a charging device that charges the surface of the above image holding body; an electrostatic latent image forming device that forms an electrostatic latent image on the surface of the charged above image holding body; a developing device that stores a developer containing toner and develops the electrostatic latent image formed on the surface of the above image holding body with the above developer to form a toner image; and the above transfer device that transfers the above toner image to the surface of the recording medium.

[0030] Effects of the invention

[0031] According to the above-described first, second, or third solution, there is provided a transfer unit which has excellent transfer maintainability to uneven paper as compared with a case where the integral value of the statistic L(r) in the intermediate transfer belt is less than 0.1 and the value of M100 / Re in the cleaning blade is less than 0.25, or a case where the integral value of the statistic L(r) in the intermediate transfer belt is less than 0.1 and the value of Re in the cleaning blade is less than 25.

[0032] According to the above-described fourth solution, there is provided a transfer unit which has excellent transfer maintainability to uneven paper as compared with a case where the number average primary particle diameter of the conductive carbon particles is greater than 20 nm.

[0033] According to the above-described fifth solution, there is provided a transfer unit which has excellent transfer maintainability to uneven paper as compared with a case where the number average primary particle diameter of the conductive carbon particles is greater than 15 nm.

[0034] According to the above-described sixth solution, there is provided a transfer unit which has excellent transfer maintainability to uneven paper as compared with a case where the conductive carbon particles are furnace black.

[0035] According to the above-described seventh solution, there is provided a transfer unit which has excellent transfer maintainability to uneven paper as compared with a case where the contact pressure of the above-described cleaning blade is less than 1.0 gf / mm or greater than 4.0 gf / mm.

[0036] According to the above-described eighth solution, there is provided a transfer device which has excellent transfer maintainability to uneven paper as compared with a case where the integral value of the statistic L(r) in the intermediate transfer belt is less than 0.1 and the value of M100 / Re in the cleaning blade is less than 0.25, or a case where the integral value of the statistic L(r) in the intermediate transfer belt is less than 0.1 and the value of Re in the cleaning blade is less than 25 in a transfer unit.

[0037] According to the above-described ninth solution, there is provided an image forming apparatus which has excellent transfer maintainability to uneven paper as compared with a case where the integral value of the statistic L(r) in the intermediate transfer belt is less than 0.1 and the value of M100 / Re in the cleaning blade is less than 0.25, or a case where the integral value of the statistic L(r) in the intermediate transfer belt is less than 0.1 and the value of Re in the cleaning blade is less than 25 in a transfer device. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 FIG. is a schematic configuration diagram showing an example of the image forming apparatus of the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0039] The following describes this embodiment. These descriptions and examples are used to illustrate the embodiment and do not limit the scope of the embodiment.

[0040] In the numerical ranges described step by step in this embodiment, the upper limit value or the lower limit value described in one numerical range can be replaced with the upper limit value or the lower limit value of the other numerical ranges described in other steps. In addition, in the numerical ranges described in this embodiment, the upper limit value or the lower limit value of the numerical range can be replaced with the value shown in the examples.

[0041] The term "step" in this embodiment includes not only independent steps, but also, even in cases where it cannot be clearly distinguished from other steps, as long as the desired purpose of the step can be achieved, it is also included in this term.

[0042] When describing the embodiments in this embodiment with reference to the drawings, the configuration of the embodiment is not limited to the configuration shown in the drawings. In addition, the sizes of the components in each drawing are schematic, and the relative relationships of the sizes between the components are not limited thereto.

[0043] Each component in this embodiment may include two or more corresponding substances. When referring to the amounts of the components in the composition in this embodiment, in cases where there are two or more substances corresponding to each component in the composition, unless otherwise specified, it refers to the total amount of the two or more substances present in the composition.

[0044] [Transfer unit]

[0045] The transfer unit of this embodiment includes:

[0046] An intermediate transfer belt as an endless belt, which is an endless belt containing resin and conductive carbon particles. In the spatial distribution of the conductive carbon particles present in an evaluation area of 6.3 μm × 4.2 μm on the outer peripheral surface, the integral value of the statistic L(r) represented by the following formula (1) where the inter-particle distance r is 0.05 μm or more and 0.30 μm or less is 0 or more and 0.1 or less; and a cleaning mechanism having a cleaning blade for cleaning the outer peripheral surface of the intermediate transfer belt. The cleaning blade is a cleaning blade that contacts the outer peripheral surface of the intermediate transfer belt. When the 100% modulus of elasticity at a specified elongation M100 (MPa) of the contact portion of the cleaning blade with the intermediate transfer belt and the resilience modulus of elasticity Re (%) of the contact portion are set, the value of M100 / Re is 0.25 or more and the value of Re is 25 or more. The transfer unit may be configured to be detachable from the image forming apparatus.

[0047] [Equation 4]

[0048]

[0049] In the above formula (1), r represents the distance between the above-mentioned particles, and K(r) represents the Ripley's K function K(r) represented by the following formula (2).

[0050] [Number 5]

[0051]

[0052] In the above formula (2), 1(|X i −X j |≤r) represents the indicator function, X i and X j represent the coordinates of point i and point j respectively, |X i −X j | represents the Euclidean distance between the coordinate X i and the coordinate X j , r represents the distance between the above-mentioned particles, s(|X i −X j |) represents the edge correction coefficient s(x) of the evaluation region represented by the following formula (3), x = |X i −X j |, N represents the total number of particles in the evaluation region, and λ represents the number density of particles in the evaluation region.

[0053] [Number 6]

[0054]

[0055] In the above formula (3), L x and L y represent the lengths (μm) of the sides of the evaluation region in the x-axis direction and the y-axis direction respectively, x = |X i −X j |, X i and X j represent the coordinates of point i and point j respectively, |X i −X j | represents the Euclidean distance between the coordinate Xi and the coordinate Xj.

[0056] Hereinafter, in the spatial distribution of the conductive carbon particles existing in the evaluation region of 6.3 μm × 4.2 μm on the outer peripheral surface of the annular belt, the integral value of the statistic L(r) represented by the formula (1) where the distance r between the particles is 0.05 μm or more and 0.30 μm or less is also referred to as the "L(r) integral value".

[0057] In addition, the conductivity in this specification means that the volume resistivity at 20 °C is less than 1×10 13 Ω·cm.

[0058] Here, the spatial distribution of the above-mentioned conductive carbon particles is obtained as follows: The outer peripheral surface of the annular belt is observed at a magnification of 20,000 times using a scanning electron microscope (for example, manufactured by Hitachi High-Technologies Corporation, model: SU8010). The obtained 256-level grayscale image is binarized with a threshold value of 128 using analysis software (for example, the free software "ImageJ") as needed, thereby obtaining this spatial distribution. Thereafter, based on the above formula, the statistic L(r) value with the particle distance r of 0.05 μm or more and 0.30 μm or less is calculated for every 0.05 μm, and the integral value in the range of 0.05 μm or more and 0.30 μm or less is obtained.

[0059] The 100% modulus of elasticity in tension M100 (MPa) is a value measured using a No. 3 dumbbell-shaped test piece at a tensile speed of 500 mm / min in accordance with JIS K6251 (2010) and obtained from the stress at 100% strain. It should be noted that, for example, a STROGRAPH AE Elastomer manufactured by Toyo Seiki Seisaku-sho, Ltd. is used as the measuring device.

[0060] In addition, the resilience modulus of elasticity is a value obtained using a Rubok type resilience testing machine in an environment of 23°C in accordance with JIS K6255 (1996).

[0061] In the present embodiment, the integral value of L(r) of the intermediate transfer belt is 0 or more and 0.1 or less, and the value of M100 / Re of the contact portion of the cleaning blade with the above-mentioned intermediate transfer belt is 0.25 or more, and the value of Re of the contact portion is 25 or more. Thus, the transfer maintainability to the embossed paper is excellent. The reason is not yet certain, but it is presumably as follows.

[0062] In an image forming apparatus using an annular belt as an intermediate transfer belt, when using embossed paper as a recording medium, when transferring a toner image from the intermediate transfer belt to the recording medium, the intermediate transfer belt cannot follow the unevenness of the recording medium, and the transferability decreases, and image blanking may occur. Specifically, for example, when the transfer electric field is enhanced because it is difficult to form a sufficient transfer electric field in the concave portion of the recording medium, an excessive electric field is locally applied to the convex portion of the recording medium, and thus abnormal discharge may occur, and the transferability may be reduced due to a decrease in the charge amount of the toner or reverse charging. In particular, in a tandem type image forming apparatus in which a plurality of monochromatic images are repeatedly printed on the intermediate transfer belt and the obtained multicolor image is transferred from the intermediate transfer belt to the recording medium, especially in an image forming apparatus using small particle size toner, the above-mentioned decrease in transferability easily becomes significant.

[0063] In addition, even if an endless belt with good transferability to the embossed paper in the initial stage is used as the intermediate transfer belt, when foreign matter adheres to the outer peripheral surface of the intermediate transfer belt as image formation progresses, abnormal discharge may occur due to the foreign matter.

[0064] In contrast, in the transfer unit of the present embodiment, the L(r) integral value of the intermediate transfer belt is 0 or more and 0.1 or less, and the value of M100 / Re of the contact portion of the cleaning blade with the intermediate transfer belt is 0.25 or more, and the value of Re of the contact portion is 25 or more.

[0065] Therefore, first, conductive carbon particles are finely dispersed on the outer peripheral surface of the intermediate transfer belt. Thus, even if the intermediate transfer belt cannot follow the unevenness of the recording medium and an excessive electric field is locally applied to the convex portions of the embossed paper, small discharges are caused at the respective conductive points finely dispersed on the outer peripheral surface of the intermediate transfer belt, and the discharges are dispersed. As a result, the charge amount of the toner due to abnormal discharge is reduced or reverse charging is suppressed, and the transferability is improved.

[0066] On the other hand, when foreign matter adheres to the outer peripheral surface of the intermediate transfer belt when the above intermediate transfer belt is used, it may prevent the dispersion of the discharges caused by the fine conductive points. However, in the present embodiment, the value of M100 / Re of the contact portion is 0.25 or more and the value of Re is 25 or more. Thereby, the cleaning blade forms a micro tack under well for the intermediate transfer belt. Here, "micro tack under" means a minute wedge-shaped space formed when the contact portion at the end of the cleaning blade contacts the outer peripheral surface of the intermediate transfer belt from the direction opposite to the transfer direction of the intermediate transfer belt for cleaning and the contact portion of the cleaning blade is drawn into the transfer direction of the intermediate transfer belt. And, in the present embodiment, by maintaining the above micro tack under, the foreign matter adhering to the surface of the intermediate transfer belt is scraped off, and the cleaning property of the intermediate transfer belt is good. Therefore, it is presumed that it is easy to maintain the good transferability to the embossed paper due to the L(r) integral value of the intermediate transfer belt being 0 or more and 0.1 or less.

[0067] Next, the endless belt used as the intermediate transfer belt and the cleaning blade used as the cleaning mechanism will be described separately.

[0068] <Intermediate transfer belt>

[0069] The endless belt used as the intermediate transfer belt contains a resin and conductive carbon particles, and the integral value of L(r) is 0 or more and 0.1 or less.

[0070] The endless belt may be a single layer or a laminate.

[0071] In the case where the annular belt is a single-layer body, the above single-layer body is a layer containing a resin and conductive carbon particles and having an integrated value of L(r) of 0 or more and 0.1 or less.

[0072] In the case where the annular belt is a laminate, the above laminate has, for example, a base material layer and a surface layer provided on the base material layer. The surface layer is the outermost layer of the annular belt. The laminate may have other layers between the base material layer and the surface layer.

[0073] In the case where the annular belt is a laminate having a base material layer and a surface layer, the above surface layer is a layer containing a resin and conductive carbon particles and having an integrated value of L(r) of 0 or more and 0.1 or less. The base material layer is not particularly limited, and examples thereof include a layer containing a resin for the base material layer and conductive carbon particles for the base material layer.

[0074] Hereinafter, the layer of the annular belt as a single-layer body is also referred to as a "single layer". In addition, the surface layer containing a resin and conductive carbon particles in the annular belt as a laminate is also referred to as a "first layer", and the base material layer containing a resin for the base material layer and conductive carbon particles for the base material layer is also referred to as a "second layer". Further, the resin and conductive carbon particles contained in the single layer or the first layer are also referred to as a "first resin" and "first conductive carbon particles", respectively, and the resin for the base material layer and conductive carbon particles for the base material layer contained in the second layer are also referred to as a "second resin" and "second conductive carbon particles", respectively.

[0075] (Resin)

[0076] Examples of the first resin contained in the single layer or the first layer include a polyimide resin (PI resin), a polyamideimide resin (PAI resin), an aromatic polyether ketone resin (e.g., an aromatic polyether ether ketone resin, etc.), a polyphenylene sulfide resin (PPS resin), a polyetherimide resin (PEI resin), a polyester resin, a polyamide resin, a polycarbonate resin, etc. From the viewpoints of mechanical strength and dispersibility of the first conductive carbon particles, the first resin preferably contains at least one selected from the group consisting of a polyimide resin, a polyamideimide resin, an aromatic polyether ketone resin, a polyetherimide resin, and a polyphenylene sulfide resin, and more preferably contains at least one selected from the group consisting of a polyimide resin and a polyamideimide resin. Among them, from the viewpoint of mechanical strength, a polyimide resin is more preferred. The first resin may be composed of one resin or may be a mixture of two or more resins.

[0077] Specific examples and preferred examples of the second resin contained in the second layer are the same as those of the first resin. The second resin may be composed of one resin or may be a mixture of two or more resins.

[0078] It should be noted that when the annular belt has a first layer and a second layer, the first resin and the second resin may be the same resin or different resins, and preferably the same resin (for example, both the first resin and the second resin are polyimide resins).

[0079] - Polyimide resin -

[0080] As the polyimide resin, for example, an imidized product of polyamic acid (a precursor of polyimide resin), which is a polymer of a tetracarboxylic dianhydride and a diamine compound, can be cited.

[0081] As the polyimide resin, for example, a resin having a structural unit represented by the following general formula (I) can be cited.

[0082] [Chemical formula 1]

[0083]

[0084] In the general formula (I), R 1 represents a tetravalent organic group, and R 2 represents a divalent organic group.

[0085] As the tetravalent organic group represented by R 1 , an aromatic group, an aliphatic group, a cycloaliphatic group, a group formed by combining an aromatic group and an aliphatic group, or a group obtained by substituting them can be cited. Specifically, as the tetravalent organic group, for example, a residue of a tetracarboxylic dianhydride described later can be cited.

[0086] As the divalent organic group represented by R 2 , an aromatic group, an aliphatic group, a cycloaliphatic group, a group formed by combining an aromatic group and an aliphatic group, or a group obtained by substituting them can be cited. Specifically, as the divalent organic group, for example, a residue of a diamine compound described later can be cited.

[0087] Specifically, as the tetracarboxylic dianhydride used as a raw material of the polyimide resin, pyromellitic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic 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)sulfone dianhydride, perylene-3,4,9,10-tetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl)ether dianhydride, ethylenetetracarboxylic dianhydride, etc. can be cited.

[0088] Specific examples of the diamine compound used as a raw material for the polyimide resin include 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl methane, 3,3'-diaminodiphenyl methane, 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, 3,3'-dimethylbenzidine, 3,3'-dimethoxybenzidine, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl propane, 2,4-bis(β-aminotert-butyl)toluene, bis(p-β-amino-tert-butylphenyl) ether, bis(p-β-methyl-δ-aminophenyl)benzene, bis-p-(1,1-dimethyl-5-aminopentyl)benzene, 1-isopropyl-2,4-m-phenylenediamine, m-xylylenediamine, p-xylylenediamine, bis(p-aminocyclohexyl)methane, 1,6-hexanediamine, heptamethylenediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, diaminopropyltetramethylene, 3-methylheptamethylenediamine, 4,4-dimethylheptamethylenediamine, 2,11-diaminododecane, 1,2-bis(3-aminopropoxy)ethane, 2,2-dimethylpropylenediamine, 3-methoxy-1,6-hexanediamine, 2,5-dimethylheptamethylenediamine, 3-methylheptamethylenediamine, 5-methyl-1,9-nonanediamine, 2,17-diaminoeicosadecane, 1,4-cyclohexanediamine, 1,10-diamino-1,10-dimethyldecane, 1,2-diaminooctadecane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, piperazine, H 2 N(CH 2 ) 3 O(CH 2 ) 2 O(CH 2 )NH 2 、H 2 N(CH 2 ) 3 S(CH 2 ) 3 NH 2 、H 2 N(CH 2 ) 3 N(CH 3 ) 2 (CH 2 ) 3 NH 2 etc.

[0089] -Polyamide-imide resin-

[0090] Examples of the polyamide-imide resin include resins having imide bonds and amide bonds in the repeating unit.

[0091] More specifically, examples of the polyamideimide resin include polymers of trivalent carboxylic acid compounds (also referred to as tricarboxylic acids) having acid anhydride groups and diisocyanate compounds or diamine compounds.

[0092] As the tricarboxylic acid, trimellitic anhydride and its derivatives are preferred. In addition to the tricarboxylic acid, tetracarboxylic dianhydrides, aliphatic dicarboxylic acids, aromatic dicarboxylic acids, etc. can also be used in combination.

[0093] 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, naphthalene-2,6-diisocyanate, etc.

[0094] Examples of the diamine compound include compounds having the same structure as the above-mentioned isocyanate and having an amino group in place of the isocyanate group.

[0095] -Aromatic polyether ketone resin-

[0096] As the aromatic polyether ketone resin, for example, resins in which aromatic rings such as benzene rings are bonded into a linear shape through ether bonds and ketone bonds can be cited.

[0097] Examples of the aromatic polyether ketone resin include: polyether ketone (PEK) in which ether bonds and ketone bonds are alternately arranged; polyether ether ketone (PEEK) in which ether bonds, ether bonds, and ketone bonds are arranged in this order; polyether ketone ketone (PEKK) in which ether bonds, ketone bonds, and ketone bonds are arranged in this order; polyether ether ketone ketone (PEEKK) in which ether bonds, ether bonds, ketone bonds, and ketone bonds are arranged in this order; polyether ketone ester containing an ester bond; and so on.

[0098] From the aspects of mechanical strength and volume resistivity adjustment, etc., the content of the first resin relative to the entire single layer is preferably 60% by mass or more and 95% by mass or less, more preferably 70% by mass or more and 95% by mass or less, and further preferably 75% by mass or more and 90% by mass or less.

[0099] From the aspects of mechanical strength and volume resistivity adjustment, etc., the content of the first resin relative to the entire first layer is preferably 60% by mass or more and 95% by mass or less, more preferably 70% by mass or more and 95% by mass or less, and further preferably 75% by mass or more and 90% by mass or less.

[0100] From the aspects of adjusting mechanical strength and volume resistivity, etc., the content of the second resin relative to the entire second layer is preferably 60% by mass or more and 95% by mass or less, more preferably 70% by mass or more and 95% by mass or less, and still more preferably 75% by mass or more and 90% by mass or less.

[0101] (Conductive carbon particles)

[0102] As the first conductive carbon particles contained in the single layer or the first layer, for example, carbon black can be cited.

[0103] As carbon black, for example, Ketjen black, oil furnace black, channel black (i.e., gas black), acetylene black, etc. can be cited. As carbon black, carbon black with a surface treatment (hereinafter also referred to as "surface-treated carbon black") can also be used.

[0104] The surface-treated carbon black is obtained by imparting, for example, carboxyl groups, quinone groups, lactone groups, hydroxyl groups, etc. to its surface. As the surface treatment method, for example, the air oxidation method of reacting with air in a high-temperature atmosphere; the method of reacting with nitrogen oxides or ozone at normal temperature (e.g., 22 °C); the method of oxidizing with ozone at low temperature after air oxidation in a high-temperature atmosphere; and so on.

[0105] As the number-average primary particle diameter of the first conductive carbon particles, for example, a range of 20 nm or less can be cited. From the aspect of adjusting the L(r) integral value to the above range, a range of 18 nm or less is preferred, a range of 15 nm or less is more preferred, and a range of 13 nm or less is still more preferred. In addition, as the number-average primary particle diameter of the first conductive carbon particles, for example, a range of 2 nm or more can be cited. From the aspect of adjusting the L(r) integral value to the above range, a range of 5 nm or more is preferred, a range of 10 nm or more is more preferred.

[0106] As the number-average primary particle diameter of the second conductive carbon particles, for example, a range of 2 nm or more and 40 nm or less can be cited. From the aspects of dispersibility, mechanical strength, volume resistivity, film-forming property, etc., a range of 20 nm or more and 40 nm or less is preferred, a range of 20 nm or more and 35 nm or less is more preferred, and a range of 20 nm or more and 28 nm or less is still more preferred.

[0107] When the annular belt has the first layer and the second layer, the number-average primary particle diameter of the first conductive carbon particles is preferably smaller than that of the second conductive carbon particles. The number-average primary particle diameter of the first conductive carbon particles is preferably 0.5 times or more and less than 1.0 times that of the second conductive carbon particles, more preferably 0.5 times or more and 0.8 times or less, and still more preferably 0.5 times or more and 0.7 times or less.

[0108] The number average primary particle diameter of the conductive carbon particles is measured by the following method.

[0109] First, a measurement sample with a thickness of 100 nm is collected from each layer of the obtained tape using a microtome, and the measurement sample is observed using a TEM (transmission electron microscope). Then, the diameter of the circle (i.e., the equivalent circle diameter) equal to the projected area of each of the 50 conductive carbon particles is used as the particle diameter, and the average value thereof is used as the number average primary particle diameter.

[0110] When the first resin contains at least one selected from the group consisting of a polyimide resin and a polyamideimide resin and a single layer or the first layer is formed using the first coating liquid described later, from the aspect of adjusting the integrated value of L(r) to the above range, the first conductive carbon particles are preferably channel black among these, and more preferably channel black whose surface has been treated.

[0111] When a single layer or the first layer is formed using the first coating liquid, as the pH of the first conductive carbon particles, for example, a range of 1.0 or more and 5.5 or less can be cited, and from the aspect of adjusting the integrated value of L(r) to the above range, a range of 1.0 or more and 3.0 or less is preferred.

[0112] In addition, when the second layer is formed using the second coating liquid described later, as the pH of the second conductive carbon particles, for example, a range of 1.0 or more and 5.5 or less can be cited, and from the aspect of adjusting the integrated value of L(r) to the above range, a range of 1.0 or more and 3.0 or less is preferred.

[0113] It should be noted that when the annular tape has a first layer formed using the first coating liquid and a second layer formed using the second coating liquid, it is preferred that the pH of the first conductive carbon particles is less than the pH of the second conductive carbon particles.

[0114] When the first resin contains at least one selected from the group consisting of a polyetherimide resin, an aromatic polyetheretherketone resin, and a polyphenylene sulfide resin and a single layer or the first layer is formed by melt extrusion described later, from the aspect of adjusting the integrated value of L(r) to the above range, the first conductive carbon particles are preferably channel black and furnace black among these, and more preferably those whose surface has not been treated.

[0115] The first conductive carbon particles may be composed of one type of conductive carbon particles or may be a mixture of two or more types of conductive carbon particles.

[0116] Specific examples of the second conductive carbon particles contained in the second layer may also be the same as the specific examples of the first conductive carbon particles.

[0117] From the aspects of reducing the integral value of L(r) and ensuring strength, the content of the first conductive carbon particles relative to the entire monolayer is preferably 10% by mass or more and 50% by mass or less, more preferably 13% by mass or more and 40% by mass or less, and still more preferably 15% by mass or more and 30% by mass or less.

[0118] From the aspects of reducing the integral value of L(r) and ensuring strength, the content of the first conductive carbon particles relative to the entire first layer is preferably 10% by mass or more and 50% by mass or less, more preferably 13% by mass or more and 40% by mass or less, and still more preferably 15% by mass or more and 30% by mass or less.

[0119] From the aspects of adjusting dispersibility, mechanical strength, and volume resistivity, the content of the second conductive carbon particles relative to the entire second layer is preferably 5% by mass or more and 40% by mass or less, more preferably 10% by mass or more and 30% by mass or less, and still more preferably 20% by mass or more and 30% by mass or less.

[0120] (Other components)

[0121] In addition to containing resin and conductive carbon particles respectively, the monolayer, the first layer, and the second layer may each contain other components.

[0122] Examples of other components include conductive agents other than conductive carbon particles, fillers for improving the strength of the belt, antioxidants for preventing thermal deterioration of the belt, surfactants for improving fluidity, heat-resistant anti-aging agents, and the like.

[0123] When other components are included in the above layers, the content of the other components is preferably greater than 0% by mass and 10% by mass or less, more preferably greater than 0% by mass and 5% by mass or less, and still more preferably greater than 0% by mass and 1% by mass or less, relative to the total mass of the layer in question.

[0124] (Properties of the endless belt)

[0125] -Integral value of L(r) of the endless belt-

[0126] The integral value of L(r) of the endless belt is 0 or more and 0.1 or less, and from the aspect of achieving good transferability to the embossed paper, it is preferably 0 or more and 0.08 or less, more preferably 0 or more and 0.06 or less.

[0127] The method for making the integral value of L(r) fall within the above range is not particularly limited. Examples include using particles with a small number-average primary particle size as the first conductive carbon particles, selecting the type of the first conductive carbon particles used, and adjusting the conditions (such as drying conditions, etc.) during the manufacturing process of the endless belt.

[0128] - Thickness of the annular belt -

[0129] From the aspect of the mechanical strength of the belt, the thickness of a single layer is preferably 60 μm or more and 120 μm or less, more preferably 80 μm or more and 120 μm or less.

[0130] From the aspects of manufacturing suitability and suppression of discharge, the thickness of the first layer is preferably 1 μm or more and 40 μm or less, more preferably 3 μm or more and 20 μm or less.

[0131] From the aspect of the mechanical strength of the belt, the thickness of the second layer is preferably 50 μm or more and 100 μm or less, more preferably 60 μm or more and 80 μm or less.

[0132] When the annular belt has the first layer and the second layer, from the aspect of good transferability to the embossed paper, the ratio of the first layer to the total thickness is preferably 3% or more and 50% or less, more preferably 5% or more and 30% or less.

[0133] It should be noted that the film thickness of each layer is measured as follows.

[0134] That is, the cross-section in the thickness direction of the annular belt is observed using an optical microscope or a scanning electron microscope, and the thickness of the layer to be measured is measured at 10 points, and the average value thereof is taken as the thickness.

[0135] - Volume resistivity of the annular belt -

[0136] From the aspect of good transferability to the embossed paper, the common logarithm of the volume resistivity when a voltage of 100 V is applied to the annular belt for 5 seconds is preferably 9.0 (logΩ·cm) or more and 13.5 (logΩ·cm) or less, more preferably 9.5 (logΩ·cm) or more and 13.2 (logΩ·cm) or less, particularly preferably 10.0 (logΩ·cm) or more and 12.5 (logΩ·cm) or less.

[0137] The measurement of the volume resistivity when a voltage of 100 V is applied to the annular belt for 5 seconds is carried out by the following method.

[0138] Using a microammeter (R8430A manufactured by Advantest Corporation) as a resistance measuring machine and a UR probe (manufactured by Mitsubishi Chemical Analysis Co., Ltd.) as a probe, the annular belt is taken at 6 points at equal intervals in the circumferential direction, and 3 points are taken at the central part and both ends in the width direction, a total of 18 points, and the volume resistivity (logΩ·cm) is measured under the conditions of a voltage of 100 V, an application time of 5 seconds, and a pressure of 1 kgf, and the average value is calculated. In addition, the measurement is carried out in an environment of a temperature of 22°C and a humidity of 55% RH.

[0139] - Surface resistivity of the annular belt -

[0140] From the aspect of good transferability to the concavo-convex paper, the common logarithm of the surface resistivity when a voltage of 100 V is applied to the outer peripheral surface of the endless belt for 3 seconds is preferably 10.0 (logΩ / sq.) or more and 15.0 (logΩ / sq.) or less, more preferably 10.5 (logΩ / sq.) or more and 14.0 (logΩ / sq.) or less, and particularly preferably 11.0 (logΩ / sq.) or more and 13.5 (logΩ / sq.) or less.

[0141] It should be noted that the unit logΩ / sq. of the above surface resistivity is a value obtained by expressing the surface resistivity as the logarithm of the resistance value per unit area, and is also denoted as log(Ω / sq.), logΩ / square, logΩ / □, etc.

[0142] The measurement of the surface resistivity when a voltage of 100 V is applied to the outer peripheral surface of the above endless belt for 3 seconds is carried out by the following method.

[0143] Using a microammeter (R8430A manufactured by Advantest Corporation) as a resistance measuring machine and a UR probe (manufactured by Mitsubishi Chemical Analytech Co., Ltd.) as a probe, six points are taken at equal intervals in the circumferential direction of the outer peripheral surface of the endless belt, and three points are taken at the central part and both ends in the width direction, for a total of 18 points. The surface resistivity (logΩ / sq.) of the outer peripheral surface of the endless belt is measured under the conditions of a voltage of 100 V, an application time of 3 seconds, and a pressure of 1 kgf, and the average value is calculated. In addition, the measurement is carried out in an environment of a temperature of 22 °C and a humidity of 55% RH.

[0144] (Manufacturing method of the endless belt)

[0145] The manufacturing method of the endless belt is not particularly limited.

[0146] In an example of the manufacturing method of the endless belt, for example, the following steps are experienced: a first coating liquid preparation step of preparing a first coating liquid containing a first resin or its precursor, first conductive carbon particles, and a first solvent; a first coating film formation step of coating the first coating liquid on the outer periphery of the material to be coated to form a first coating film; and a first drying step of drying the first coating film while raising the temperature of the material to be coated. In the manufacturing method of the above endless belt, other steps may also be experienced in addition to the first coating liquid preparation step, the first coating film formation step, and the first drying step. As other steps, for example, in the case of using a precursor of the first resin, a first firing step of firing the first coating film dried by the first drying step can be cited.

[0147] When manufacturing the annular belt as a single-layer body, through the above-described first coating liquid preparation step, first coating film formation step, and first drying step, a single layer containing the first resin and the first conductive carbon particles is formed on the outer peripheral surface of the material to be coated. It should be noted that the single layer can be formed, for example, by preparing pellets containing the first resin and the first conductive carbon particles and melt-extruding the pellets.

[0148] When manufacturing the annular belt as a laminate, for example, through the above-described first coating liquid preparation step, first coating film formation step, and first drying step, a first layer containing the first resin and the first conductive carbon particles is formed on the outer peripheral surface of the second layer formed on the material to be coated.

[0149] When manufacturing the annular belt as a laminate, for example, the second layer is formed on the outer peripheral surface of the material to be coated by going through the following steps: a second coating liquid preparation step of preparing a second coating liquid containing a second resin or its precursor, second conductive carbon particles, and a second solvent; a second coating film formation step of coating the second coating liquid on the outer periphery of the material to be coated to form a second coating film; and a second drying step of drying the second coating film. It should be noted that the second layer can also be formed, for example, by preparing pellets containing the second resin and the second conductive carbon particles and melt-extruding the pellets.

[0150] - Coating Liquid Preparation Step -

[0151] In the first coating liquid preparation step, a first coating liquid containing a first resin or its precursor, first conductive carbon particles, and a first solvent is prepared. For example, when the first resin is a polyimide resin and the first conductive carbon particles are carbon black, as the first coating liquid, for example, a solution in which carbon black is dispersed and a polyamic acid as a polyimide resin precursor is dissolved in the first solvent is prepared. Additionally, for example, when the first resin is a polyamide-imide resin and the first conductive carbon particles are carbon black, as the first coating liquid, for example, a solution in which carbon black is dispersed and the polyamide-imide resin is dissolved in the first solvent is prepared.

[0152] As a method for preparing the first coating liquid, from the aspect of crushing the aggregates of the first conductive carbon particles and from the aspect of improving the dispersibility of the first conductive carbon particles, it is preferable to stir the conductive carbon particles using a planetary mixer and then perform a dispersion treatment using a crusher such as a ball mill or a jet mill.

[0153] The first solvent is not particularly limited and can be appropriately determined according to the type of resin used as the first resin, etc. For example, when the first resin is a polyimide resin or a polyamide-imide resin, as the first solvent, it is preferable to use the polar solvent described later.

[0154] As polar solvents, for example, N-methyl-2-pyrrolidone (NMP), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N,N-diethylacetamide (DEAc), dimethyl sulfoxide (DMSO), hexamethylphosphoramide (HMPA), N-methylcaprolactam, N-acetyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone (N,N-dimethylimidazolidinone, DMI), etc. can be cited. They can be used alone or in combination of two or more.

[0155] It should be noted that in the case of undergoing the second coating liquid preparation step, in the second coating liquid preparation step, a second coating liquid containing a second resin, second conductive carbon particles, and a second solvent is prepared. The second resin and the second conductive carbon particles are as described above, and the preparation method of the second coating liquid and the second solvent are the same as the preparation method of the first coating liquid and the first solvent respectively.

[0156] - Coating film formation step -

[0157] In the first coating film formation step, the above-mentioned first coating liquid is coated on the outer periphery of the material to be coated to form a first coating film.

[0158] As the material to be coated, for example, a cylindrical or columnar mold, etc. can be cited. The material to be coated can be a material obtained by applying an anti-sticking agent to the outer peripheral surface of the above-mentioned mold. In the case of manufacturing an annular belt as a single layer, in the first coating film formation step, for example, the first coating liquid is directly coated on the outer peripheral surface of the above-mentioned material to be coated or the material to be coated applied with an anti-sticking agent. In the case of manufacturing an annular belt as a laminate, in the first coating film formation step, for example, the first coating liquid is coated on the outer peripheral surface of the material to be coated on which the second layer or the second coating film is formed.

[0159] As the coating method of the first coating liquid, for example, well-known methods such as spraying method, spiral coating (flow coating) method, blade coating method, wire bar coating method, dip coating method, microbead coating method, air knife coating method, curtain coating method, etc. can be cited.

[0160] It should be noted that in the case of undergoing the second coating film formation step, in the second coating film formation step, the second coating liquid is coated on the outer periphery of the material to be coated to form a second coating film. The coating method of the second coating liquid is also the same as that of the first coating liquid.

[0161] - Drying step -

[0162] In the first drying step, the first coating film formed in the first coating film formation step is dried. The first solvent contained in the first coating film is removed through the first drying step to obtain a single layer or the first layer.

[0163] As a method for drying the first coating film, for example, a method of supplying hot air to the first coating film, a method of heating the coated material, etc. can be cited.

[0164] As the hot air velocity on the surface of the first coating film, for example, a range of 0.1 m / s or more and 50.0 m / s or less can be cited, preferably a range of 1.0 m / s or more and 40.0 m / s or less, more preferably a range of 1.0 m / s or more and 20.0 m / s or less.

[0165] Here, the hot air velocity on the surface of the first coating film is measured as follows. Specifically, it is measured using an anemometer (Anemomaster model 6036 manufactured by KANOMAX).

[0166] As the hot air temperature on the surface of the first coating film, for example, a range of 50°C or more and 200°C or less can be cited, preferably a range of 80°C or more and 185°C or less, more preferably a range of 110°C or more and 170°C or less.

[0167] The hot air temperature on the surface of the first coating film is measured by connecting a thermometer (for example, K thermocouple of Graphtec, model: JBS-7115-5M-K) to a data logger of Graphtec (model: GL240).

[0168] The method of supplying hot air to the surface of the first coating film is not particularly limited. For example, a method of blowing the hot air of the drying furnace from a slit nozzle onto the surface of the first coating film, a method of directly supplying the hot air of the drying furnace to the first coating film, etc. can be cited. Among them, from the aspect of easily controlling the hot air velocity on the surface of the first coating film, the method using a slit nozzle is preferred.

[0169] It should be noted that in the case of undergoing a second drying step, in the second drying step, the second coating film formed by the second coating film forming step is dried. The method of drying the second coating film is the same as the method of drying the first coating film. The second drying step can be completed before the first coating film forming step, or the first coating film forming step can be carried out before completing the second drying step, making the first drying step also serve as a part of the second drying step.

[0170] -Firing step-

[0171] As described above, the manufacturing method of the annular belt can undergo a first firing step. In the first firing step, firing is carried out by heating the first coating film dried by the first drying step. For example, when the first resin is a polyimide resin, the polyamic acid in the first coating film is imidized through the first firing step to obtain polyimide.

[0172] The heating temperature in the first firing step may be, for example, in the range of 150°C or higher and 450°C or lower, preferably in the range of 200°C or higher and 430°C or lower. In addition, the heating time in the first firing step may be, for example, in the range of 20 minutes or longer and 180 minutes or shorter, preferably in the range of 60 minutes or longer and 150 minutes or shorter.

[0173] It should be noted that in the case of manufacturing an annular belt as a laminate, when forming the second layer through the second coating liquid preparation step, the second coating film formation step, and the second drying step, a second firing step of firing the second coating film dried by the second drying step may be performed. The second firing step may also serve as the first firing step.

[0174] <Cleaning blade>

[0175] The cleaning blade used as the cleaning mechanism is a cleaning blade that contacts the outer peripheral surface of the intermediate transfer belt. There is no particular limitation as long as the value of M100 / Re at the contact portion with the intermediate transfer belt is 0.25 or more and the value of Re is 25 or more.

[0176] Hereinafter, a component with a value of M100 / Re of 0.25 or more and a value of Re of 25 or more will also be referred to as a "contact component".

[0177] (Composition)

[0178] The cleaning blade may be, for example, a single-layer structure, a two-layer structure, a structure with three or more layers, or other structures.

[0179] As a cleaning blade with a single-layer structure, for example, a cleaning blade in which the entire part including the contact portion is made of a single material (i.e., a cleaning blade formed by a contact component) can be cited.

[0180] As a cleaning blade with a two-layer structure, for example, a cleaning blade provided with a first layer and a second layer can be cited. The first layer is formed on the entire surface on the ventral side including the contact portion and is formed by a contact component, and the second layer is formed as a back layer on the back side relative to the first layer and is formed of a material different from the contact component.

[0181] As a cleaning blade with a structure of three or more layers, for example, a cleaning blade having another layer between the first layer and the second layer in the above-mentioned two-layer structure cleaning blade can be cited.

[0182] The cleaning blade is used, for example, by being bonded to a rigid plate-like support material.

[0183] (Composition of contact component)

[0184] The contact member is not particularly limited as long as the value of M100 / Re is 0.25 or more and the value of Re is 25 or more.

[0185] As the contact member, for example, a member containing polyurethane rubber can be cited.

[0186] - Polyurethane rubber -

[0187] The polyurethane rubber is a polyurethane rubber formed by polymerizing at least a polyol component and a polyisocyanate component. The polyurethane rubber can be a polyurethane rubber formed by polymerizing, in addition to the polyol component, a resin having a functional group capable of reacting with the isocyanate group of the polyisocyanate as needed.

[0188] The polyurethane rubber preferably has a hard segment and a soft segment. The "hard segment" and the "soft segment" refer to the following segments: in the polyurethane rubber material, the material constituting the former is formed of a material relatively harder than the material constituting the latter, and the material constituting the latter is formed of a material relatively softer than the material constituting the former.

[0189] It should be noted that, as the material constituting the hard segment (hard segment material), a low molecular weight polyol component in the polyol component, a resin having a functional group capable of reacting with the isocyanate group of the polyisocyanate, etc. can be cited. On the other hand, as the material constituting the soft segment (soft segment material), a high molecular weight polyol component in the polyol component can be cited.

[0190] Here, the average particle diameter of the aggregate of the hard segment is preferably 1 μm or more and 10 μm or less, more preferably 1 μm or more and 5 μm or less.

[0191] By making the average particle diameter of the aggregate of the hard segment 1 μm or more, the frictional resistance of the surface of the contact member is easily reduced. Therefore, the wiper behavior becomes stable and local wear is easily suppressed.

[0192] On the other hand, by making the average particle diameter of the aggregate of the hard segment 10 μm or less, the occurrence of breakage is easily suppressed.

[0193] The average particle diameter of the aggregate of the hard segment is measured as follows. An image is taken at a magnification of ×20 using a polarizing microscope (BX51-P manufactured by Olympus), and image processing is performed to binarize the image. Five locations are measured for each cleaning blade (the particle diameters of five aggregates are measured for each location), and the particle diameters (equivalent circle diameters) of the aggregates are measured for 20 cleaning blades, and the average particle diameter is calculated from a total of 500 aggregates.

[0194] It should be noted that for the binarization of the image, the image processing software OLYMPUS Streamessentials (manufactured by Olympus Corporation) is used to adjust the thresholds of hue / saturation / brightness so that the crystal part and the aggregates of the hard segments are black and the amorphous part (corresponding to the soft segments) is white.

[0195] · Polyol component

[0196] The polyol component includes a high molecular weight polyol and a low molecular weight polyol.

[0197] The high molecular weight polyol component is a polyol having a number average molecular weight of 500 or more (preferably 500 or more and 5000 or less). As the high molecular weight polyol component, known polyols such as polyester polyols obtained by dehydration condensation of low molecular weight polyols and dibasic acids, polycarbonate polyols obtained by reaction of low molecular weight polyols and alkyl carbonates, polycaprolactone polyols, and polyether polyols can be cited. It should be noted that as commercially available products of high molecular weight polyols, for example, PRAXCELL 205, PRAXCELL 240, etc. manufactured by Daicel Corporation can be cited.

[0198] Here, the number average molecular weight is a value measured by the gel permeation chromatography (GPC) method. The same applies hereinafter.

[0199] These high molecular weight polyols can be used alone or in combination of two or more.

[0200] The polymerization ratio of the high molecular weight polyol component can be 30 mol% or more and 50 mol% or less, preferably 40 mol% or more and 50 mol% or less, based on all the polymerization components of the polyurethane rubber.

[0201] The low molecular weight polyol component is a polyol having a molecular weight (number average molecular weight) of less than 500. The low molecular weight polyol is a material that functions as a chain extender and a crosslinking agent.

[0202] As the low molecular weight polyol component, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, 1,20-eicosanediol can be cited. Among them, as the low molecular weight polyol component, 1,4-butanediol is preferably used.

[0203] As the low molecular weight polyol component, known diols (2-functional), triols (3-functional), or tetraols (4-functional), etc. that are used as chain extenders and crosslinking agents can also be cited.

[0204] These polyols can be used alone or in combination of two or more.

[0205] With respect to all the polymerization components of the polyurethane rubber, the polymerization ratio of the low molecular weight polyol component can be more than 50 mol% and 75 mol% or less, preferably 52 mol% or more and 75 mol% or less, more preferably 55 mol% or more and 75 mol% or less, and further preferably 55 mol% or more and 60 mol% or less.

[0206] · Polyisocyanate component

[0207] Examples of the polyisocyanate component include 4,4'-diphenylmethane diisocyanate (MDI), 2,6-toluene diisocyanate (TDI), 1,6-hexane diisocyanate (HDI), 1,5-naphthalene diisocyanate (NDI), and 3,3-dimethylbiphenyl-4,4-diisocyanate (TODI).

[0208] As the polyisocyanate component, 4,4'-diphenylmethane diisocyanate (MDI), 1,5-naphthalene diisocyanate (NDI), and hexamethylene diisocyanate (HDI) are more preferred.

[0209] These polyisocyanate components can be used alone or in combination of two or more.

[0210] With respect to all the polymerization components of the polyurethane rubber, the polymerization ratio of the polyisocyanate component can be 5 mol% or more and 25 mol% or less, preferably 10 mol% or more and 20 mol% or less.

[0211] · Resin having a functional group reactive with an isocyanate group

[0212] The resin having a functional group reactive with an isocyanate group (hereinafter referred to as "functional group-containing resin") is preferably a resin having flexibility, and from the aspect of flexibility, an aliphatic resin having a linear structure is more preferred. Specific examples of the functional group-containing resin include acrylic resins containing two or more hydroxyl groups, polybutadiene resins containing two or more hydroxyl groups, and epoxy resins having two or more epoxy groups.

[0213] As commercially available products of acrylic resins containing two or more hydroxyl groups, for example, ACTFLOW manufactured by Soken Chemical & Engineering Co., Ltd. (grades: UMB-2005B, UMB-2005P, UMB-2005, UME-2005, etc.) can be cited.

[0214] As commercially available products of polybutadiene resins containing two or more hydroxyl groups, for example, R-45HT manufactured by Idemitsu Kosan Co., Ltd. can be cited.

[0215] As an epoxy resin having two or more epoxy groups, it is not a resin having hard and brittle properties like common existing epoxy resins, but is preferably a resin that is softer and more tough than existing epoxy resins. As the above epoxy resin, for example, in terms of molecular structure, a resin having a structure (flexible skeleton) that can improve the mobility of the main chain in its main chain structure is suitable. As the flexible skeleton, an alkylene skeleton, a cycloalkane skeleton, a polyoxyalkylene skeleton, etc. can be cited, and a polyoxyalkylene skeleton is particularly suitable.

[0216] In addition, in terms of physical properties, compared with existing epoxy resins, an epoxy resin having a lower viscosity compared to its molecular weight is suitable. Specifically, it is preferably in the range of 900 ± 100 in terms of its weight average molecular weight and in the range of 15000 ± 5000 mPa·s at 25°C, and more preferably in the range of 15000 ± 3000 mPa·s in terms of this viscosity. As a commercially available product of an epoxy resin having this property, for example, EPICLCON EXA-4850-150 manufactured by DIC can be cited.

[0217] The polymerization ratio of the resin containing the functional group may be in a range that does not impair the effect of the cleaning blade of the present embodiment.

[0218] · Method for manufacturing polyurethane rubber

[0219] The manufacturing of polyurethane rubber uses common manufacturing methods of polyurethane such as the prepolymer method or the one-step method. The prepolymer method can obtain a polyurethane having excellent abrasion resistance and breakage resistance, so it is suitable for the present embodiment, but it is restricted by the manufacturing method.

[0220] It should be noted that in the molding of the cleaning blade, the composition for forming the cleaning blade prepared by the above method is formed into a sheet by, for example, centrifugal molding or extrusion molding, and is manufactured by performing cutting processing, etc.

[0221] Here, as the catalyst used in the manufacturing of polyurethane rubber, amine compounds such as tertiary amines, quaternary ammonium salts, and organometallic compounds such as organotin compounds can be cited.

[0222] As the above tertiary amine, for example, trialkylamines such as triethylamine, tetraalkyl diamines such as N,N,N’,N’-tetramethyl-1,3-butanediamine, amino alcohols such as dimethylethanolamine, ethoxylated amines, ethoxylated diamines, amines such as bis(diethyl ethanolamine) adipate, triethylenediamine (TEDA), cyclohexylamine derivatives such as N,N-dimethylcyclohexylamine, morpholine derivatives such as N-methylmorpholine, N-(2-hydroxypropyl)-dimethylmorpholine, and piperazine derivatives such as N,N’-diethyl-2-methylpiperazine, N,N’-bis(2-hydroxypropyl)-2-methylpiperazine, etc. can be cited.

[0223] As quaternary ammonium salts, examples include 2-hydroxypropyltrimethylammonium octoate, 1,5-diazabicyclo[4.3.0]nonene-5 (DBN) octoate, 1,8-diazabicyclo[5.4.0]undecene-7 (DBU)-octoate, DBU-oleate, DBU-p-toluenesulfonate, DBU-formate, 2-hydroxypropyltrimethylammonium formate, and the like.

[0224] As organotin compounds, examples include dialkyltin compounds such as dibutyltin dilaurate and dibutyltin bis(2-ethylhexanoate), and stannous 2-ethylhexanoate, stannous oleate, and the like.

[0225] Among these catalysts, triethylenediamine (TEDA) as a tertiary amine is used from the aspect of hydrolysis resistance, and a quaternary ammonium salt is preferably used from the aspect of processability. Among the quaternary ammonium salts, 1,5-diazabicyclo[4.3.0]nonene-5 (DBN) octoate, 1,8-diazabicyclo[5.4.0]undecene-7 (DBU)-octoate, and DBU-formate with high reactivity are preferably used.

[0226] The content of the catalyst is preferably in the range of 0.0005% by mass or more and 0.03% by mass or less, particularly preferably 0.001% by mass or more and 0.01% by mass or less, based on the entire polyurethane rubber constituting the contact member.

[0227] These components can be used alone or in combination of two or more.

[0228] (Physical properties of the contact member)

[0229] The value of M100 / Re of the contact member is 0.25 or more, preferably 0.28 or more, more preferably 0.3 or more. It should be noted that from the aspect of damage resistance, the upper limit of the value of M100 / Re of the contact member is preferably 1.0 or less, more preferably 0.9 or less.

[0230] The Re [%] of the contact member is 25% or more, preferably 28% or more, more preferably 30% or more. It should be noted that from the aspects of suppressing squeegee chatter and abrasion resistance, the upper limit of Re [%] of the contact portion is preferably 60% or less, more preferably 40% or less.

[0231] From the aspects of abrasion resistance and damage resistance, the M100 [MPa] of the contact member is preferably 4 MPa or more and 10 MPa or less, more preferably 5 MPa or more and 9 MPa or less.

[0232] By making the value of M100 / Re 0.25 or more and the value of Re 25 or more, compared with the case where the value of Re is less than 25, it is not easy to form a state in which the contact portion of the cleaning blade is significantly involved in the conveyance direction of the intermediate transfer belt, and it is possible to suppress the case where it is difficult to recover from the significantly involved state.

[0233] By making the value of M100 / Re 0.25 or more and the value of Re 25 or more, compared with the case where the value of M100 / Re is less than 0.25 and the value of Re is less than 25, it is easy to form a minute area turnover, and it is possible to suppress the occurrence of color stripes due to the dragging of the front end of the cleaning blade.

[0234] The method for controlling the value of M100 / Re and the value of Re of the contact member is not particularly limited. For example, in the case where the contact member contains polyurethane rubber, a method of adjusting to the above range by selecting the type and amount of each polymer component of the polyurethane rubber and the manufacturing conditions can be cited.

[0235] It should be noted that the weight average molecular weight of the contact member may be 1000 or more and 4000 or less, preferably 1500 or more and 3500 or less.

[0236] The above weight average molecular weight is a value measured by gel permeation chromatography (GPC) method.

[0237] (Composition of non-contact member)

[0238] In the cleaning blade, the composition of the non-contact member in the case where the contact member and the area other than the contact member (hereinafter also referred to as "non-contact member") are made of different materials is described.

[0239] The non-contact member may be made of any known material without particular limitation as long as it has a function of supporting the contact member. Specifically, as the material used in the non-contact member, for example, polyurethane rubber, silicone rubber, fluororubber, chloroprene rubber, butadiene rubber, etc. can be cited. Among these, polyurethane rubber is preferred. As the polyurethane rubber, ester-based polyurethane and ether-based polyurethane can be cited, and ester-based polyurethane is particularly preferred.

[0240] (Manufacture of cleaning blade)

[0241] As a single-layer structure cleaning blade, it is manufactured, for example, by the above-described forming method of the contact member.

[0242] The cleaning blade as a two-layer structure and the cleaning blade as a structure of three or more layers are produced, for example, by bonding the first layer as a contact member and the second layer as a non-contact member (two or more layers in the case of a layer structure of three or more layers) to each other. As the bonding method, double-sided tapes, various adhesives, etc. are preferably used. In addition, it is also possible to set a time difference during molding so that the materials of each layer flow into the mold, and bond two or more layers by the combination between the materials without providing an adhesive layer.

[0243] (Contact with the intermediate transfer belt)

[0244] The cleaning blade is fixed in the cleaning housing, for example, in such a manner that the front end of the contact portion becomes the opening portion side, and the cleaning housing has an opening portion on the intermediate transfer belt side. The cleaning housing includes, for example, a transfer member that guides foreign matters such as waste toner recovered from the outer peripheral surface of the intermediate transfer belt by the cleaning blade to a foreign matter recovery container.

[0245] The cleaning mechanism may have two or more cleaning blades.

[0246] The force NF (normal force) with which the cleaning blade presses against the intermediate transfer belt, that is, the contact pressure, is preferably in the range of 1.0 gf / mm or more and 4.0 gf / mm or less, and more preferably in the range of 1.5 fgf / mm or more and 3.5 fgf / mm.

[0247] In addition, the length by which the contact portion of the cleaning blade bites into the intermediate transfer belt is preferably in the range of 0.8 mm or more and 1.2 mm or less, and more preferably in the range of 0.9 mm or more and 1.1 mm or less.

[0248] [Transfer device, image forming device]

[0249] The transfer device of the present embodiment includes: a transfer unit including an intermediate transfer belt and a cleaning mechanism that cleans the outer peripheral surface of the intermediate transfer belt; a primary transfer mechanism that primarily transfers the toner image formed on the surface of the image carrier to the surface of the intermediate transfer belt of the transfer unit; and a secondary transfer mechanism that secondarily transfers the toner image transferred to the surface of the intermediate transfer belt to the surface of the recording medium, and the transfer device of the present embodiment uses the above transfer unit as the transfer unit.

[0250] The image forming device of the present 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 surface of the charged image carrier; a developing device that stores a developer containing toner and develops the electrostatic latent image formed on the surface of the image carrier with the developer to form a toner image; and a transfer device that transfers the toner image to the surface of the recording medium, and uses the above transfer device as the transfer device.

[0251] The image forming device of this embodiment includes, for example: a normal monochrome image forming device in which only monochrome toner is stored in a developing device; a color image forming device that repeatedly transfers the toner image held on an image holding body to an intermediate transfer belt in sequence; and a tandem color image forming device in which two or more image holding bodies having developers for each color are arranged in series on the intermediate transfer belt.

[0252] Figure 1 This is a schematic structural diagram showing an example of the image forming apparatus according to the present embodiment. Figure 1 The image forming apparatus shown is an image forming apparatus in which the endless belt in the above-mentioned transfer unit is applied to the intermediate transfer belt 107 , and the cleaning blade in the above-mentioned transfer unit is applied to the intermediate transfer belt cleaning device 112 .

[0253] As shown in the figure, the image forming apparatus 100 of the present embodiment is, for example, a so-called tandem type, and charging devices 102a to 102d, exposure devices 114a to 114d, developing devices 103a to 103d, primary transfer devices (primary transfer rollers) 105a to 105d, and image holder cleaning devices 104a to 104d are sequentially arranged around four image holders 101a to 101d formed by electrophotographic photosensitive bodies along their rotation direction. It should be noted that in order to remove the residual potential remaining on the surface of the image holders 101a to 101d after transfer, a static remover may be provided.

[0254] The intermediate transfer belt 107 is given tension and supported by supporting rollers 106a to 106d, a driving roller 111, and an opposing roller 108, forming a transfer unit 107b. By using these supporting rollers 106a to 106d, driving rollers 111, and opposing rollers 108, the intermediate transfer belt 107 can move between each image holder 101a to 101d and the primary transfer rollers 105a to 105d in the direction of arrow A while contacting the surface of each image holder 101a to 101d. The portion where the primary transfer rollers 105a to 105d contact the image holder 101a to 101d across the intermediate transfer belt 107 is the primary transfer portion, and a primary transfer voltage is applied to the contact portion between the image holder 101a to 101d and the primary transfer rollers 105a to 105d.

[0255] As a secondary transfer device, the opposing roller 108 and the secondary transfer roller 109 are disposed opposite to each other with the intermediate transfer belt 107 and the secondary transfer belt 116 therebetween. The secondary transfer belt 116 is supported by the secondary transfer roller 109 and the support roller 106e. A recording medium 115 such as paper contacts the surface of the intermediate transfer belt 107 and simultaneously moves in the direction of arrow B in the region clamped by the intermediate transfer belt 107 and the secondary transfer roller 109, and then passes through the fixing device 110. The portion where the secondary transfer roller 109 contacts the opposing roller 108 with the intermediate transfer belt 107 and the secondary transfer belt 116 therebetween is the secondary transfer portion, and a secondary transfer voltage is applied to the contact portion between the secondary transfer roller 109 and the opposing roller 108. Further, the intermediate transfer belt cleaning devices 112 and 113 are disposed in such a manner as to contact the intermediate transfer belt 107 after transfer.

[0256] In the multi-color image forming apparatus 100 having this configuration, the image carrier 101a rotates in the direction of arrow C, and its surface is charged by the charging device 102a, and then an electrostatic latent image of the first color is formed by an exposure device 114a such as a laser. The formed electrostatic latent image is developed (imaged) by a developer containing toner by a developing device 103a storing toner corresponding to this color to form a toner image. It should be noted that in the developing devices 103a to 103d, toners corresponding to electrostatic latent images of various colors (for example, yellow, magenta, cyan, black) are stored respectively.

[0257] The toner image formed on the image carrier 101a is electrostatically transferred (primary transfer) to the intermediate transfer belt 107 by the primary transfer roller 105a when passing through the primary transfer portion. Then, on the intermediate transfer belt 107 holding the toner image of the first color, primary transfer is performed in such a manner that toner images of the second color, the third color, and the fourth color are sequentially overlapped by the primary transfer rollers 105b to 105d, and finally a multi-color multi-toner image is obtained.

[0258] The multi-toner image formed on the intermediate transfer belt 107 is electrostatically transferred at once to the recording medium 115 conveyed by the secondary transfer belt 116 when passing through the secondary transfer portion. The recording medium 115 onto which the toner image has been transferred is conveyed to the fixing device 110, and after being subjected to fixing processing by heating and pressurization, heating or pressurization, it is discharged outside the apparatus.

[0259] After primary transfer, the image carriers 101a to 101d are cleaned of residual toner by the image carrier cleaning devices 104a to 104d. On the other hand, after secondary transfer, the intermediate transfer belt 107 is cleaned of residual toner by the intermediate transfer belt cleaning devices 112 and 113 and is placed in the following image forming process.

[0260] (Image carrier)

[0261] As the image holding members 101a to 101d, well-known electrophotographic photoreceptors are widely used. As the electrophotographic photoreceptor, an inorganic photoreceptor having a photosensitive layer made of an inorganic material, an organic photoreceptor having a photosensitive layer made of an organic material, etc. are used. Among the organic photoreceptors, a function-separated organic photoreceptor in which a charge generation layer that generates charges by exposure and a charge transport layer that transports charges are laminated is preferably used; a single-layer organic photoreceptor that functions to generate charges and transport charges. In addition, among the inorganic photoreceptors, a photoreceptor having a photosensitive layer made of amorphous silicon is preferably used.

[0262] In addition, the shape of the image holding member is not particularly limited, and for example, well-known shapes such as a cylindrical drum shape, a sheet shape, or a plate shape are adopted.

[0263] (Charging device)

[0264] There is no particular limitation on the charging devices 102a to 102d. For example, well-known chargers such as contact chargers using a conductive roller, brush, film, or rubber blade, etc., and a scorotron charger or a corotron charger using corona discharge are widely used. Among them, a contact charger is preferred.

[0265] The charging devices 102a to 102d usually apply a direct current to the image holding members 101a to 101d, but an alternating current may be further superimposed and applied.

[0266] (Exposure device)

[0267] There is no particular limitation on the exposure devices 114a to 114d. For example, well-known exposure devices such as light sources such as semiconductor lasers, LED (Light Emitting Diode) lights, or liquid crystal shutter lights, or optical system devices that can expose an image determined by these light sources through a prism are widely used.

[0268] (Developing device)

[0269] As the developing devices 103a to 103d, they are selected according to the purpose. For example, well-known developers that develop a one-component developer or a two-component developer using a brush or a roller in a contact or non-contact manner can be cited.

[0270] (Primary transfer roller)

[0271] The primary transfer rollers 105a to 105d can be either single-layer or multi-layer. For example, in the case of a single-layer structure, the roller is composed of a roller in which conductive particles such as carbon black are appropriately mixed in foamed or non-foamed silicone rubber, urethane rubber, or EPDM.

[0272] (Image holding member cleaning device)

[0273] The image holding member cleaning devices 104a to 104d are used to remove the residual toner attached to the surfaces of the image holding members 101a to 101d after the primary transfer step. In addition to the cleaning blade, brush cleaning or roller cleaning, etc. are also used. Among them, it is preferable to use a cleaning blade. In addition, as the material of the cleaning blade, urethane rubber, neoprene rubber, silicone rubber, etc. can be cited.

[0274] (Secondary transfer roller)

[0275] The layer structure of the secondary transfer roller 109 is not particularly limited. For example, in the case of a three-layer structure, it is composed of a core layer, an intermediate layer, and a coating layer covering its surface. The core layer is composed of a foam such as silicone rubber, urethane rubber, or EPDM in which conductive particles are dispersed, and the intermediate layer is composed of their non-foamed bodies. As the material of the coating layer, tetrafluoroethylene-hexafluoropropylene copolymer, perfluoroalkoxy resin, etc. can be cited. The volume resistivity of the secondary transfer roller 109 is preferably 10 7 Ωcm or less. In addition, a two-layer structure other than the intermediate layer can also be used.

[0276] (Counter roller)

[0277] The counter roller 108 forms the counter electrode of the secondary transfer roller 109. The layer structure of the counter roller 108 can be either a single layer or a multi-layer. For example, in the case of a single layer structure, it is composed of a roller in which conductive particles such as carbon black are appropriately mixed in silicone rubber, urethane rubber, or EPDM, etc. In the case of a two-layer structure, it is composed of a roller in which the outer peripheral surface of an elastic layer made of the above-mentioned rubber material is covered with a high-resistance layer.

[0278] A voltage of usually 1 kV or more and 6 kV or less is applied to the cores of the counter roller 108 and the secondary transfer roller 109. It is also possible not to apply a voltage to the core of the counter roller 108, but to apply a voltage to a highly conductive electrode member in contact with the counter roller 108 and the secondary transfer roller 109. As the above-mentioned electrode member, a metal roller, a conductive rubber roller, a conductive brush, a metal plate, or a conductive resin plate, etc. can be cited.

[0279] (Fusing device)

[0280] As the fusing device 110, a well-known fuser such as a heat roller fuser, a pressure roller fuser, or a flash fuser, etc. is widely used.

[0281] (Intermediate transfer belt cleaning device)

[0282] The intermediate transfer belt cleaning device 112 is the cleaning blade in the above-mentioned transfer unit.

[0283] As the intermediate transfer belt cleaning device 113, in addition to the cleaning blade, brush cleaning, roller cleaning, etc. are also used.

[0284] The above describes the present embodiment, but it should not be construed as being limited to the above embodiment, and various deformations, changes, and improvements can be made.

[0285] [Examples]

[0286] The following describes the examples of the present invention, but the present invention is not limited to the following examples. It should be noted that in the following description, unless otherwise specified, "parts" and "%" are all based on mass.

[0287] [Manufacture of Intermediate Transfer Belt (Endless Belt)]

[0288] [Manufacture of Intermediate Transfer Body A]

[0289] To 1000 g of a wholly aromatic polyimide varnish (solid content rate: 18 wt%, manufactured by Unitika, U-Imide KX, solvent: NMP), 38 g (21 phr) of oxidized gas black (channel black, manufactured by Orion Engineered Carbons S.A., FW200, number average primary particle size: 13 nm) as the first conductive carbon particles was added, and the resulting composition was passed through holes of, and dispersion was carried out by performing an operation of colliding the slurry divided into two parts 5 times, to obtain coating liquid A as the first coating liquid.

[0290] The obtained coating liquid A was coated onto the outer surface of a SUS pipe by the flow coating method so as to obtain a prescribed film thickness, rotated and dried at 150 °C for 30 minutes, then placed in an oven at 340 °C for 1 hour, and then taken out, thereby obtaining a SUS pipe having an endless belt A formed on the outer surface. The overall film thickness of the endless belt A (i.e., the film thickness of a single layer) was 80 μm.

[0291] The endless belt A coated on the outer surface was removed from the SUS pipe and cut into a width of 360 mm to obtain intermediate transfer body A as a belt-shaped intermediate transfer body. It should be noted that the content of the conductive carbon particles relative to the entire intermediate transfer body A was 17 mass%.

[0292] In addition, the volume resistivity and the surface resistivity of the outer peripheral surface of the intermediate transfer body A were measured by the above method. As a result, the common logarithm of the volume resistivity was 10.1 (logΩ·cm), and the common logarithm of the surface resistivity was 10.5 (logΩ / sq.).

[0293] <Manufacture of Intermediate Transfer Body B>

[0294] The annular belt B and the intermediate transfer body B are obtained in the same manner as the annular belt A and the intermediate transfer body A, except that oxidized gas black (channel black, manufactured by Orion Engineered Carbons S.A., SB6) is used instead of oxidized gas black (manufactured by Orion Engineered Carbons S.A., FW200).

[0295] The overall film thickness of the annular belt B (i.e., the film thickness of a single layer) is 78 μm.

[0296] The content of conductive carbon particles in the entire intermediate transfer body B is 20% by mass, the common logarithm of the volume resistivity of the intermediate transfer body B is 10.3 (logΩ·cm), and the common logarithm of the surface resistivity of the intermediate transfer body B is 10.8 (logΩ / sq.).

[0297] <Manufacture of Intermediate Transfer Body C>

[0298] The annular belt C and the intermediate transfer body C are obtained in the same manner as the annular belt A and the intermediate transfer body A, except that in the drying step, a slit nozzle is used to heat at 150 °C for 15 minutes instead of rotary drying at 150 °C for 30 minutes.

[0299] The overall film thickness of the annular belt C (i.e., the film thickness of a single layer) is 81 μm.

[0300] The content of conductive carbon particles in the entire intermediate transfer body C is 17% by mass, the common logarithm of the volume resistivity of the intermediate transfer body C is 10.1 (logΩ·cm), and the common logarithm of the surface resistivity of the intermediate transfer body C is 10.4 (logΩ / sq.).

[0301] <Manufacture of Intermediate Transfer Body D>

[0302] The annular belt D and the intermediate transfer body D are obtained in the same manner as the annular belt A and the intermediate transfer body A, except that rotary drying is performed at 130 °C for 45 minutes instead of at 150 °C for 30 minutes.

[0303] The overall film thickness of the annular belt D (i.e., the film thickness of a single layer) is 81 μm.

[0304] The content of conductive carbon particles in the entire intermediate transfer body D is 17% by mass, the common logarithm of the volume resistivity of the intermediate transfer body D is 10.2 (logΩ·cm), and the common logarithm of the surface resistivity of the intermediate transfer body D is 10.6 (logΩ / sq.).

[0305] <Manufacture of Intermediate Transfer Bodies E and F>

[0306] Instead of rotary drying at 150°C for 30 minutes, heating was performed at 165°C using a slit nozzle. Other than this, endless belts E and F, and intermediate transfer members E and F were obtained in the same manner as endless belt A and intermediate transfer member A, respectively. Regarding the heating time using the slit nozzle, it was 12 minutes for endless belt E and 10 minutes for endless belt F.

[0307] The overall film thickness (i.e., the film thickness of a single layer) of both endless belt E and endless belt F was 80 μm.

[0308] The content of conductive carbon particles with respect to the entire intermediate transfer member E and the content of conductive carbon particles with respect to the entire endless belt F were both 17% by mass. The common logarithm of the volume resistivity of intermediate transfer member E and intermediate transfer member F was both 10.1 (logΩ·cm), and the common logarithm of the surface resistivity of intermediate transfer member E and intermediate transfer member F was both 10.5 (logΩ / sq.).

[0309] <Fabrication of Intermediate Transfer Member G>

[0310] Instead of using oxidized gas black (channel black, manufactured by Orion Engineered Carbons S.A., SB4) to replace oxidized gas black (manufactured by Orion Engineered Carbons S.A., FW200), endless belt G and intermediate transfer member G were obtained in the same manner as endless belt A and intermediate transfer member A.

[0311] The overall film thickness (i.e., the film thickness of a single layer) of endless belt G was 80 μm.

[0312] The content of conductive carbon particles with respect to the entire intermediate transfer member G was 16% by mass. The common logarithm of the volume resistivity of intermediate transfer member G was 10.3 (logΩ·cm), and the common logarithm of the surface resistivity of intermediate transfer member G was 10.9 (logΩ / sq.).

[0313] [Fabrication of Cleaning Blade]

[0314] <Fabrication of Cleaning Blades 1 - 6>

[0315] By changing the types and molar ratios of the high molecular polyol component, low molecular polyol component, isocyanate component, and crosslinking agent, as well as the curing and maturation conditions according to Table 1, each single-layer cleaning blade was fabricated. Specifically as follows.

[0316] First, adipic acid (HOOC - C 4 H 8-COOH) and 1,4-butanediol were polymerized at a molar ratio of 1:1, and the ends were treated to be -OH to obtain a polyester polyol polymerized with a straight-chain diol (butanediol) having 4 carbon atoms. The number-average molecular weight of the obtained polyester polyol was 2000.

[0317] Next, the polyester polyol as the high-molecular polyol component, 1,4-butanediol (1,4-BD, chain extender) as the low-molecular polyol, 4,4'-diphenylmethane diisocyanate (MDI, polyisocyanate, manufactured by Tosoh Corporation, Millionate MT) as the isocyanate, and trimethylolpropane (TMP, manufactured by Mitsubishi Gas Chemical Company, Inc.) as the crosslinking agent were reacted at 80 °C for 2 hours in a nitrogen atmosphere according to the mixing amounts (molar ratios) shown in Table 1 to prepare a cleaning blade-forming composition A1.

[0318] Next, the above cleaning blade-forming composition A1 was poured into a centrifugal molding machine with the mold adjusted to 140 °C, cured under the curing and aging conditions shown in Table 1, and then subjected to aging heating. After that, the cooled cured product was cut to obtain a cleaning blade with a width of 8 mm and a thickness of 2 mm.

[0319] It should be noted that the curing and aging conditions A to D shown in Table 1 are as follows.

[0320] · Curing and aging condition A: After curing reaction at 100 °C for 1 hour, aging heating was carried out at 110 °C for 24 hours

[0321] · Curing and aging condition B: After curing reaction at 110 °C for 1 hour, aging heating was carried out at 110 °C for 24 hours

[0322] · Curing and aging condition C: After curing reaction at 110 °C for 2 hours, aging heating was carried out at 110 °C for 48 hours

[0323] · Curing and aging condition D: After curing reaction at 100 °C for 40 minutes, aging heating was carried out at 100 °C for 24 hours

[0324] [Table 1]

[0325]

[0326] [Measurement of intermediate transfer belt and cleaning blade]

[0327] The L(r) integral value in the intermediate transfer belt, the M100 / Re value in the cleaning blade, and the Re value in the cleaning blade were measured by the above method, and the results are shown in Table 2.

[0328] [Manufacture of image forming apparatus]

[0329] The combination of the intermediate transfer belt and the cleaning blade shown in Table 2 was assembled into a modified image forming apparatus (manufactured by Fuji Xerox Co., Ltd., DocuColor-7171P), that is, a modified apparatus in which after installing the transfer belt, the cleaning blade was adjusted according to the film thickness of the belt, to obtain the image forming apparatuses of Examples 1 to 4 and Comparative Examples 1 to 3.

[0330] It should be noted that the force NF, i.e., the contact pressure, at which the cleaning blade presses against the intermediate transfer belt is 1.1 gf / mm.

[0331] [Evaluation of Transfer Unit]

[0332] [Evaluation of Transferability to Embossed Paper]

[0333] In an environment of a temperature of 22°C and a humidity of 55%, a blue solid image was formed on embossed paper (Lesac 66, 204 gsm), and the initial image quality (initial image quality) was visually evaluated. In addition, 10,000 sheets of the above solid images were formed, and the image quality of the 10,000th image (image quality after 10kPV) was visually evaluated. The evaluation criteria are as follows, and the results are shown in Table 2.

[0334] - Evaluation Criteria -

[0335] A: No transfer unevenness or color streaks were confirmed.

[0336] B: Extremely slight transfer unevenness occurred.

[0337] C: Unacceptable transfer unevenness occurred.

[0338] D: Color streaks occurred.

[0339] [Table 2]

[0340]

[0341] From the results shown in Table 2 above, it can be seen that compared with the transfer units of the comparative examples, the transfer units of the present examples are excellent in transfer maintainability when using a recording medium with large surface irregularities.

Claims

1. A transfer unit, comprising: An intermediate transfer belt as a loop belt, which is a loop belt containing a resin and conductive carbon particles. In the spatial distribution of the conductive carbon particles present in an evaluation area of 6.3 μm × 4.2 μm on the outer peripheral surface, the integral value of the statistic L(r) represented by the following formula (1) where the inter-particle distance r is 0.05 μm or more and 0.30 μm or less is 0 or more and 0.1 or less, and A cleaning mechanism having a cleaning blade for cleaning the outer peripheral surface of the intermediate transfer belt. The cleaning blade is a cleaning blade that contacts the outer peripheral surface of the intermediate transfer belt. When the 100% modulus at a specified elongation M100 (MPa) of the contact portion of the cleaning blade with the intermediate transfer belt is set and the resilience modulus of the contact portion is set to Re (%), the value of M100 / Re is 0.25 or more and the value of Re is 25 or more, In the above formula (1), r represents the inter-particle distance, and K(r) represents Ripley's K function K(r) represented by the following formula (2), In the above formula (2), 1(|X i −X j |≤r) represents an indicator function, X i and X j represent the coordinates of point i and point j respectively, |X i −X j | represents the Euclidean distance between the coordinate X i and the coordinate X j , r represents the above-mentioned inter-particle distance, s(|X i −X j |) represents the edge correction coefficient s(x) of the evaluation region represented by the following formula (3), x = |X i −X j |, N represents the total number of particles in the evaluation region, and λ represents the number density of particles in the evaluation region. In the above formula (3), L x and L y respectively represent the lengths (μm) of the sides in the x-axis direction and y-axis direction of the evaluation region, x = |X i −X j |, X i and X j respectively represent the coordinates of point i and point j, and |X i −X j | represents the Euclidean distance between the coordinate Xi and the coordinate Xj.

2. The transfer unit according to claim 1, wherein, The resin contains at least one selected from the group consisting of polyimide resin, polyamide-imide resin, aromatic polyether ether ketone resin, polyphenylene sulfide resin, and polyetherimide resin.

3. The transfer unit according to claim 2, wherein, The resin contains polyimide resin.

4. The transfer unit according to any one of claims 1 to 3, wherein, The number average primary particle diameter of the conductive carbon particles is 10 nm or more and 20 nm or less.

5. The transfer unit according to claim 4, wherein, The number average primary particle diameter of the conductive carbon particles is 10 nm or more and 15 nm or less.

6. The transfer unit according to any one of claims 1 to 3, wherein, The conductive carbon particles are channel black.

7. For the transfer unit according to any one of claims 1 to 3, the contact pressure of the cleaning blade with respect to the intermediate transfer belt is 1.0 gf / mm or more and 4.0 gf / mm or less.

8. A transfer device, comprising: The transfer unit according to any one of claims 1 to 7, A primary transfer mechanism for primarily transferring the toner image formed on the surface of the image carrier to the surface of the intermediate transfer belt of the transfer unit, and A secondary transfer mechanism for secondarily transferring the toner image transferred to the surface of the intermediate transfer belt to the surface of the recording medium.

9. An image forming apparatus, comprising: 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 the surface of the charged image carrier, A developing device for storing a developer containing toner and developing the electrostatic latent image formed on the surface of the image carrier with the developer to form a toner image, and The transfer device according to claim 8 for transferring the toner image to the surface of the recording medium.

Images