Image forming apparatus and image forming method

Abstract

To provide an image forming apparatus with excellent toner image fixation properties in recesses of recording media. [Solution] An image forming apparatus comprising: a developing means for containing an electrostatic image developer containing toner in which the number proportion of toner particles with a particle size of 4 μm or less is 15% or more; and a fixing device having a fixing member which is a cured product of a composition containing an organopolysiloxane (Type T) that does not contain fluorine atoms and has a silsesquioxane structure and a dimethylorganopolysiloxane (Type D), the content ratio of Type T to Type D (Type T / Type D) is 1 / 9 or more and 9 / 1 or less, and the difference ΔH between the maximum and minimum values ​​of ultrafine hardness is 0% or more and 50% or less.

Description

[Technical Field]

[0001] This disclosure relates to an image forming apparatus and an image forming method. [Background technology]

[0002] In electrophotographic image forming apparatuses, an image is formed by bringing a fixing member into contact with a toner image transferred onto a recording medium, applying heat and pressure, and fixing the toner image to the recording medium.

[0003] For example, Patent Document 1 discloses a heat fixing roll in which at least the surface layer is made of silicone rubber cured from a polyorganosiloxane composition that basically consists of (A) polyorganosiloxane, (B) a curing agent, and (C) polymethylsilsesquioxane. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 158362 / 1983 [Overview of the project] [Problems that the invention aims to solve]

[0005] The object of this disclosure is to provide an image forming apparatus and an image forming method that exhibit superior toner image fixation in recesses of a recording medium, even when forming an image with an electrostatic image developer containing toner in which the number ratio of toner particles with a particle size of 4 μm or less is 15% or more on a recording medium with irregularities, compared to an image forming apparatus equipped with a fixing member having a surface layer which is a cured product of a composition with a content ratio (T-type / D-type) of less than 1 / 9 or greater than 9 / 1, or a surface layer in which the difference ΔH between the maximum and minimum values ​​of ultrafine hardness is greater than 50%. [Means for solving the problem]

[0006] Means for solving the above problems include the following aspects. <1> An image carrier, Charging means for charging the surface of the image carrier, Electrostatic charge image forming means for forming an electrostatic charge image on the charged surface of the image carrier, Developing means for accommodating an electrostatic charge developer containing toner having a toner particle size of 4 μm or less and a toner particle number ratio of 15% or more, and developing the electrostatic charge image formed on the surface of the image carrier as a toner image using the electrostatic charge developer, Transfer means for transferring the toner image to a recording medium, An organopolysiloxane (T-type) having a silsesquioxane structure represented by the following formula 1 and containing no fluorine atom, and a dimethyloorganopolysiloxane (D-type), and a cured product of a composition having a content ratio (T-type / D-type) of the organopolysiloxane (T-type) and the dimethyloorganopolysiloxane (D-type) of 1 / 9 or more and 9 / 1 or less, and having a surface layer in which the difference ΔH between the maximum value and the minimum value of the ultra-micro hardness measured at any 50 points by the ultra-micro hardness test defined in JIS Z2255 (2003) is 0% or more and 50% or less. A fixing device for fixing the toner image on the recording medium by bringing the surface layer of the fixing member into contact with the toner image on the recording medium and performing heating and pressurization, An image forming apparatus comprising: Formula 1 [R 2 , 2 , 2 , 2 , 1 , m , , 1 , 1 , 3 / 2 , SiO 3 / 2 m (In Formula 1, R 1 each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aralkyl group, an aryl group, a group represented by -C(=O)-CR 2 3, or a monovalent organic group having a reactive group. A plurality of R 1 may be the same or different from each other. R 2 represents a hydrogen atom, a methyl group, or an ethyl group. When there are a plurality of R 2 , the plurality of R 2 ​These may be the same or different. The monovalent organic group may be substituted with a halogen atom, a hydroxyl group, an alkoxy group, an aryloxy group, an aralkyloxy group, or an oxy group. The alkyl group, alkenyl group, alkynyl group, aralkyl group, and aryl group may have substituents. m represents a positive integer. <2> The content ratio (Type T / Type D) in the above composition is 3 / 7 or more and 7 / 3 or less. <1> The image forming apparatus described above. <3> The surface layer has a difference ΔH between the maximum and minimum values ​​of the ultramicrohardness of 0% or more and 40% or less. <1> or <2> The image forming apparatus described above. <4> The aforementioned surface layer has a tensile elongation of 50% or more. <1> ~ <3> An image forming apparatus as described in any one of the items. <5> The aforementioned surface layer has a tensile elongation of 70% or more. <4> The image forming apparatus described. <6> The fixing member has an elastic layer and the surface layer on the elastic layer, The average thickness of the surface layer is 30 μm or less, and the average thickness of the elastic layer is 300 μm or more. <1> ~ <5> An image forming apparatus as described in any one of the items. <7> The average thickness of the surface layer is 10 μm or more and 50 μm or less, and the average thickness of the elastic layer is 150 μm or more and 600 μm or less. <6> The image forming apparatus described above. <8> The aforementioned R 1 At least one of them is a methyl group or a phenyl group. <1> ~ <7> An image forming apparatus as described in any one of the items. <9> The aforementioned R 1 At least one of them is a methyl group. <8> The image forming apparatus described above. <10> A charging step in which the surface of the image holder is charged, A step of forming an electrostatic image on the surface of the charged image holder, A developing step in which an electrostatic image developer containing toner having a particle size of 4 μm or less and a number ratio of 15% or more of toner particles is used to develop the electrostatic image formed on the surface of the image holder as a toner image, A transfer step of transferring the toner image formed on the surface of the image holder to the surface of the recording medium, A fixing step in which a toner image is fixed to a recording medium by bringing the surface layer of a fixing member into contact with the toner image on the recording medium and applying heat and pressure, the fixing member having a surface layer having a surface layer having a surface layer where the difference ΔH between the maximum and minimum values ​​of ultramicrohardness measured at 50 arbitrary points according to the ultramicrohardness test specified in JIS Z2255 (2003) is 0% or more and 50% or less, and the surface layer of the fixing member having a surface layer having a surface layer having a surface layer where the difference ΔH between the maximum and minimum values ​​of ultramicrohardness is 0% or more and 50% or less, the surface layer of the fixing member having a surface layer has been brought into contact with the toner image on the recording medium and the toner image is fixed to the recording medium, An image forming method having the following characteristics. Equation 1 [R 1 SiO 3 / 2 ] m (In Equation 1, R 1 Each of these independently represents a hydrogen atom, alkyl group, alkenyl group, alkynyl group, aralkyl group, aryl group, and -C(=O)-CR 2 Represents a group represented by 3, or a monovalent organic group having a reactive group. Multiple R 1 These may be the same or different. R 2 R represents a hydrogen atom, a methyl group, or an ethyl group. 2 If you have multiple R 2 These may be the same or different. The monovalent organic group may be substituted with a halogen atom, a hydroxyl group, an alkoxy group, an aryloxy group, an aralkyloxy group, or an oxy group. The alkyl group, alkenyl group, alkynyl group, aralkyl group, and aryl group may have substituents. m represents a positive integer. [Effects of the Invention]

[0007] <1> , <8> , or <9> According to the present invention, compared to an image forming apparatus equipped with a fixing member having a surface layer which is a cured product of a composition with a content ratio (Type T / Type D) of less than 1 / 9 or greater than 9 / 1, or a surface layer in which the difference ΔH between the maximum and minimum values ​​of ultrafine hardness is greater than 50%, an image forming apparatus is provided that exhibits superior fixing of toner images in recesses of a recording medium, even when forming an image with an electrostatic image developer containing toner in which the number ratio of toner particles with a particle size of 4 μm or less is 15% or more on a recording medium having irregularities. <2> According to the present invention, compared to an image forming apparatus equipped with a surface layer which is a cured product of a composition having a content ratio (Type T / Type D) of less than 3 / 7 or greater than 7 / 3, an image forming apparatus is provided that exhibits superior fixing of toner images in recesses of a recording medium, even when forming an image with an electrostatic image developer containing toner in which the number ratio of toner particles with a particle size of 4 μm or less is 15% or more on a recording medium having irregularities. <3> According to the present invention, compared to an image forming apparatus equipped with a fixing member having a surface layer in which the difference ΔH between the maximum and minimum values ​​of ultra-micro hardness is more than 40%, an image forming apparatus is provided that exhibits superior fixing of toner images in recesses of a recording medium, even when forming an image with an electrostatic image developer containing toner in which the number ratio of toner particles with a particle size of 4 μm or less is 15% or more on a recording medium having irregularities. <4> or <5> According to the present invention, compared to an image forming apparatus equipped with a fixing member having a surface layer with a tensile elongation rate of less than 50%, an image forming apparatus is provided that exhibits superior fixing of toner images in recesses of a recording medium, even when forming an image with an electrostatic image developer containing toner in which the number ratio of toner particles with a particle size of 4 μm or less is 15% or more on a recording medium having an uneven surface. <6> or <7> According to the present invention, compared to an image forming apparatus equipped with a fixing member having an average surface layer thickness of more than 30 μm or an elastic layer thickness of less than 300 μm, an image forming apparatus is provided that exhibits superior fixing of toner images in recesses of a recording medium, even when forming an image with an electrostatic image developer containing toner in which the number ratio of toner particles with a particle size of 4 μm or less is 15% or more on a recording medium having irregularities. <10> According to the invention, compared to an image forming method in which the fixing process is performed using a fixing member having a surface layer which is a cured product of a composition with a content ratio (T-type / D-type) of less than 1 / 9 or greater than 9 / 1, or a surface layer in which the difference between the maximum and minimum values ​​of ultrafine hardness ΔH is greater than 50%, an image forming method is provided in which an image is formed using an electrostatic image developer containing toner in which the number ratio of toner particles with a particle size of 4 μm or less is 15% or more on a recording medium having irregularities, and in which an image is formed using an electrostatic image developer. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic cross-sectional view showing an example of a fixing member used in this embodiment. [Figure 2] This is a schematic diagram showing an example of a first embodiment of the fixing device used in this embodiment. [Figure 3] This is a schematic diagram showing an example of a second embodiment of the fixing device used in this embodiment. [Figure 4] This is a schematic diagram showing an example of a third embodiment of the fixing device used in this embodiment. [Figure 5] This is a schematic diagram showing an example of an image forming apparatus according to this embodiment. [Modes for carrying out the invention]

[0009] An example embodiment of this disclosure will be described. These descriptions and examples are illustrative and do not limit the scope of the invention. In this specification, a numerical range represented by "~" means a range that includes the numbers before and after "~" as lower and upper limits, unless those numbers are preceded by "greater than" or "less than". If the numbers before and after "~" are preceded by "greater than" or "less than", the numerical range means a range that does not include those numbers as lower or upper limits. In the numerical ranges described stepwise in this specification, the upper limit of one stepwise numerical range may be replaced with the upper limit of another stepwise numerical range, or with the values ​​shown in the examples. Similarly, the lower limit of one stepwise numerical range may be replaced with the lower limit of another stepwise numerical range, or with the values ​​shown in the examples. Furthermore, unless otherwise specified, the percentage (%) used for content refers to "mass%". A percentage of "0" indicates that the component is optional and does not need to be included.

[0010] Each component may contain multiple types of the relevant substance. When referring to the amount of each component in a composition, if there are multiple substances corresponding to each component in the composition, unless otherwise specified, it refers to the total amount of those multiple substances present in the composition. The term "process" includes not only independent processes, but also any process that cannot be clearly distinguished from other processes, as long as its intended function is achieved.

[0011] <Image forming apparatus> An image forming apparatus according to the embodiment of the present disclosure comprises: an image holder; charging means for charging the surface of the image holder; electrostatic image forming means for forming an electrostatic image on the charged surface of the image holder; developing means for containing an electrostatic image developer and developing the electrostatic image formed on the surface of the image holder as a toner image using the electrostatic image developer; transfer means for transferring the toner image to a recording medium; and fixing apparatus for fixing the toner image to a recording medium by bringing the surface layer of a fixing member into contact with the toner image on the recording medium and applying heat and pressure. Furthermore, the electrostatic image developer contains toner in which the number percentage of toner particles with a particle size of 4 μm or less is 15% or more. Furthermore, the surface layer of the fixing member is a cured product of a composition containing an organopolysiloxane (Type T) having a silsesquioxane structure represented by the following formula 1, and a dimethylorganopolysiloxane (Type D), wherein the content ratio of organopolysiloxane (Type T) to dimethylorganopolysiloxane (Type D) (Type T / Type D) is 1 / 9 or more and 9 / 1 or less. The surface layer has a difference ΔH between the maximum and minimum ultramicrohardness values ​​when measured at 50 arbitrary points using the ultramicrohardness test specified in JIS Z2255 (2003), which is 0% or more and 50% or less. Note that the content ratio (Type T / Type D) represents the mass ratio.

[0012] Conventionally, toners containing a large amount of fine toner particles (specifically, toner particles with a particle size of 4 μm or less) have been used. For example, toners that have been made smaller in diameter to meet the demand for improved toner image quality contain a large amount of fine toner particles. In fine toner particles, the proportion of inclusions such as external additives is relatively high, so fine toner particles have poor heat transfer properties. Furthermore, recording media with uneven surfaces such as embossed paper (for example, Lezack 66 (manufactured by Tokushu Tokai Paper Co., Ltd., surface unevenness difference 80 μm, 151 g / m²) 2 Examples include: ( ) In these cases, there are areas in the recesses of the uneven surface where the fixing member does not make contact, resulting in reduced toner adhesion in those areas. Therefore, when forming an image on a recording medium with an uneven surface, such as embossed paper, using a toner containing a large amount of fine toner particles, it is necessary to improve the adhesion of the fine toner particles in the recesses of the recording medium.

[0013] In contrast, in the image forming apparatus according to this embodiment, the surface layer of the fixing member is formed by a cured product of a composition containing organopolysiloxane (Type T) having a silsesquioxane structure and dimethyl organopolysiloxane (Type D) in the aforementioned ratio. Therefore, while release properties from toner are ensured in the surface layer, the flexibility of the surface layer is enhanced by the inclusion of dimethyl organopolysiloxane (Type D). In other words, even when using a recording medium with irregularities, the ability of the fixing member to conform to recesses is enhanced, and high fixing performance can be obtained even when using toner containing a large amount of fine toner particles.

[0014] The embodiments of this disclosure will be described in more detail below.

[0015] [Fixing member] The fixing device includes a fixing member. The fixing member has at least a surface layer and may further have a base material, and may have an elastic layer between the base material and the surface layer. The fixing member fixes the toner image to the recording medium by bringing the surface layer into contact with the toner image on the recording medium and applying heat and pressure. The shape of the fixing member may be, for example, belt-shaped.

[0016] (Surface layer) The surface layer of the fixing member does not contain fluorine atoms. "Does not contain fluorine atoms" means that it does not contain compounds that contain fluorine atoms (F) in their molecular structure. Examples of compounds that contain fluorine atoms (F) in their molecular structure include fluororesins such as tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), polytetrafluoroethylene (PTFE), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), polyethylene-tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), and vinyl fluoride (PVF).

[0017] The surface layer is a cured product of a composition (hereinafter also referred to as the "specified composition") containing an organopolysiloxane (Type T) having a silsesquioxane structure represented by the following formula 1, and a dimethylorganopolysiloxane (Type D). The content ratio (Type T / Type D) of organopolysiloxane (Type T) to dimethylorganopolysiloxane (Type D) in the specified composition is 1 / 9 or more and 9 / 1 or less.

[0018] • Organopolysiloxane (Type T) The following describes organopolysiloxanes (T-type) having a silsesquioxane structure represented by Formula 1 below. Equation 1 [R 1 SiO 3 / 2 ] m (In Equation 1, R 1 Each of these independently represents a hydrogen atom, alkyl group, alkenyl group, alkynyl group, aralkyl group, aryl group, and -C(=O)-CR 2 Represents a group represented by 3, or a monovalent organic group having a reactive group. Multiple R 1 These may be the same or different. R 2 R represents a hydrogen atom, a methyl group, or an ethyl group. 2 If you have multiple R 2 These may be the same or different. The monovalent organic group may be substituted with a halogen atom, a hydroxyl group, an alkoxy group, an aryloxy group, an aralkyloxy group, or an oxy group. The alkyl group, alkenyl group, alkynyl group, aralkyl group, and aryl group may have substituents. m represents a positive integer.

[0019] Organopolysiloxane (T-type) has a silsesquioxane structure represented by formula 1 (i.e., "R" 1 SiO 3 / 2 It has only the constituent units represented by ".

[0020] R 1This includes hydrogen atoms, alkyl groups, alkenyl groups, alkynyl groups, aralkyl groups, aryl groups, and -C(=O)-CR groups. 2 At least one selected from the group consisting of the group represented by 3, or a monovalent organic group having a reactive group (hereinafter also referred to as a "polymerizable functional group"). If m is 2 or more, there are multiple R 1 They may be the same or they may be different.

[0021] R 1 The alkyl group may be an alkyl group. The alkyl group may be either an aliphatic group or an alicyclic group, and may be linear or branched. The alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 4 carbon atoms, even more preferably 1 to 2 carbon atoms, and particularly preferably 1 carbon atom, i.e., a methyl group. Specific examples of alkyl groups with 1 to 10 carbon atoms include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, and decyl groups.

[0022] R 1 The group may be an alkenyl group. The alkenyl group may be an aliphatic group, an alicyclic group, or an aromatic group, and may be linear or branched. The number of carbon atoms in the alkenyl group is preferably 1 to 10. Specific examples of alkenyl groups with 1 to 10 carbon atoms include ethenyl (vinyl) group, orthostyryl group, metastyryl group, parastyryl group, 1-propenyl group, 2-propenyl (allyl) group, 1-butenyl group, 1-pentenyl group, 3-methyl-1-butenyl group, phenylethenyl group, allyl (2-propenyl) group, and octenyl (7-octen-1-yl) group.

[0023] R 1The group may be an alkynyl group. The alkynyl group may be an aliphatic group, an alicyclic group, or an aromatic group, and may be linear or branched. Preferably, the alkynyl group has 1 to 10 carbon atoms. Specific examples of alkynyl groups include ethynyl group, 1-propynyl group, 1-butynyl group, 1-pentynyl group, 3-methyl-1-butynyl group, and phenylbutynyl group.

[0024] R 1 This may be an aralkyl group. The aralkyl group preferably has 7 to 20 carbon atoms, and more preferably 7 to 10 carbon atoms. Examples of aralkyl groups with 7 to 20 carbon atoms include phenylalkyl groups such as benzyl groups.

[0025] R 1 This may be an aryl group. The aryl group preferably has 6 to 20 carbon atoms, more preferably 6 to 10 carbon atoms, and even more preferably 6 carbon atoms, i.e., a phenyl group. Examples of aryl groups with 6 to 20 carbon atoms include a phenyl group, a 1-naphthyl group, and a 2-naphthyl group.

[0026] R 1 is -C(=O)-CR 2 3 is also acceptable. 2 R represents a hydrogen atom, a methyl group, or an ethyl group. 2 It is preferable that it is a methyl group. 2 If you have multiple R 2 These may be the same or different.

[0027] R 1The polymerizable functional group may be a monovalent organic group having a reactive group (polymerizable functional group). Examples of polymerizable functional groups include those that can be thermoset or photocured. There are no particular limitations on polymerizable functional groups, but examples include vinyl groups, allyl groups, styryl groups, methacryloyl groups, acryloyl groups, acryloyloxy groups, methacryloyloxy groups, α-methylstyryl groups, vinyl ether groups, vinyl ester groups, acrylamide groups, methacrylamide groups, N-vinylamide groups, maleic acid ester groups, fumaric acid ester groups, N-substituted maleimide groups, isocyanate groups, oxetanyl groups, and epoxy groups. Among these, polymerizable functional groups having any of (meth)acryloyl groups, oxetanyl groups, and epoxy groups are preferred. The polymerizable functional group may further be substituted with a halogen atom, a hydroxyl group, an alkoxy group, an aryloxy group, an aralkyloxy group, or an oxy group.

[0028] As polymerizable functional groups having a (meth)acryloyl group, for example, groups represented by the following formula or groups containing this group are preferred.

[0029] [ka]

[0030] In the above formula, R 4 R represents a hydrogen atom or a methyl group. 5 R represents an alkylene group with 1 to 10 carbon atoms. 4 As such, an alkylene group having 2 to 10 carbon atoms is preferred.

[0031] The oxetanyl group is not particularly limited, but examples include the (3-ethyl-3-oxetanyl)methyloxy group and the (3-ethyl-3-oxetanyl)oxy group. The polymerizable functional group having an oxetanyl group is preferably the group represented by the following formula, or a group containing this formula.

[0032] [ka]

[0033] In the above formula, R 6 R represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. 7 R represents an alkylene group with 1 to 6 carbon atoms. 6 The hydrogen atom, methyl group, ethyl group, etc. are preferred, and the ethyl group is more preferred. 7 Preferably, the alkylene group has 2 to 6 carbon atoms, and a propylene group is more preferable.

[0034] Polymerizable functional groups having epoxy groups are not particularly limited, but examples include alkyl groups having 1 to 10 carbon atoms substituted with glycidoxy groups such as β-glycidoxyethyl, γ-glycidoxypropyl, and γ-glycidoxybutyl; and alkyl groups having 5 to 10 carbon atoms substituted with oxirane groups such as glycidyl, β-(3,4-epoxycyclohexyl)ethyl, γ-(3,4-epoxycyclohexyl)propyl, β-(3,4-epoxycycloheptyl)ethyl, 4-(3,4-epoxycyclohexyl)butyl, and 5-(3,4-epoxycyclohexyl)pentyl.

[0035] Polymerizable functional groups may be functional groups having a carbon-carbon double bond or a carbon-carbon triple bond that can undergo a hydrosilylation reaction with a hydrogen atom bonded to a silicon atom (hydrosilyl group). Unsaturated organic groups can also function as polymerizable functional groups in the sense that, due to the presence of a hydrogen atom in the hydrosilyl group, they polymerize with that hydrogen atom through a hydrosilylation reaction to form a hydrosilylated structural portion. Specific examples of such unsaturated organic groups include the alkenyl group and alkynyl group mentioned above. While not particularly limited, examples of unsaturated organic groups include vinyl group, orthostyryl group, metastyryl group, parastyryl group, acryloyl group, methacryloyl group, acryloxy group, methacryloxy group, 1-propenyl group, 1-butenyl group, 1-pentenyl group, 3-methyl-1-butenyl group, phenylethenyl group, ethynyl group, 1-propynyl group, 1-butynyl group, 1-pentynyl group, 3-methyl-1-butynyl group, phenylbutynyl group, allyl(2-propenyl) group, and octenyl(7-octen-1-yl) group. Such unsaturated organic groups are preferably any of vinyl group, parastyryl group, allyl(2-propenyl) group, and octenyl(7-octen-1-yl) group, with vinyl group being more preferred.

[0036] Furthermore, the organopolysiloxane (T-type) having the silsesquioxane structure represented by Formula 1 may contain two or more polymerizable functional groups. In this case, all polymerizable functional groups may be identical or different. Also, multiple polymerizable functional groups may be identical, and further different polymerizable functional groups may be included.

[0037] R 1 The alkyl groups, alkenyl groups, and alkynyl groups represented by these terms are aralkyl groups, aryl groups, and -C(=O)-CR groups. 23. Both the polymerizable functional group and the 3. polymerizable functional group may have substituents. Such substituents include halogen atoms such as fluorine, chlorine, bromine, and chlorine atoms; alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, s-butyl, isobutyl, t-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, and isooctyl groups; hydroxyl groups; alkoxy groups; aryloxy groups; aralkyloxy groups; oxy groups (=O); cyano groups; and protected hydroxyl groups, at least one of these.

[0038] The protecting group of a protected hydroxyl group is not particularly limited, and known hydroxyl protecting groups can be used. For example, such protecting groups include acyl protecting groups represented by -C(=O)R (wherein R is an alkyl group having 1 to 6 carbon atoms, such as a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, and n-pentyl group; or a phenyl group with or without a substituent. The substituents of a phenyl group with a substituent include alkyl groups such as a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, s-butyl group, isobutyl group, t-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, and isooctyl group; and fluorine atoms, chlorine atoms, and bromine atoms. Examples of protecting groups include rogen atoms (such as alkoxy groups like methoxy and ethoxy groups), silyl protecting groups such as trimethylsilyl, triethylsilyl, t-butyldimethylsilyl, and t-butyldiphenylsilyl groups; acetal protecting groups such as methoxymethyl, methoxyethoxymethyl, 1-ethoxyethyl, tetrahydropyran-2-yl, and tetrahydrofuran-2-yl groups; alkoxycarbonyl protecting groups such as t-butoxycarbonyl groups; and ether protecting groups such as methyl, ethyl, t-butyl, octyl, allyl, triphenylmethyl, benzyl, p-methoxybenzyl, fluorenyl, trityl, and benzhydryl groups.

[0039] In Equation 1, R 1Preferably, at least one of them is a methyl group or a phenyl group, and more preferably a methyl group.

[0040] The number of silsesquioxane structures represented by formula 1 (i.e., the number of m) in organopolysiloxanes (T-type) is a positive integer.

[0041] • Dimethylorganopolysiloxane (Type D) Dimethyl organopolysiloxane (Type D) has the structure represented by the following formula 2. Equation 2 [R 3 2SiO 2 / 2 ] n (In equation 2, R 3 Each of these independently represents a hydrogen atom, alkyl group, alkenyl group, alkynyl group, aralkyl group, aryl group, and -C(=O)-CR 2 Represents a group represented by 3, or a monovalent organic group having a reactive group. Multiple R 3 These may be the same or different. R 2 R represents a hydrogen atom, a methyl group, or an ethyl group. 2 If you have multiple R 2 These may be the same or different. The monovalent organic group may be substituted with a halogen atom, a hydroxyl group, an alkoxy group, an aryloxy group, an aralkyloxy group, or an oxy group. The alkyl group, alkenyl group, alkynyl group, aralkyl group, and aryl group may have substituents. n represents a positive integer.

[0042] Dimethylorganopolysiloxane (Type D) has a molecular structure represented by the structure shown in Equation 2 (i.e., "R 3 2SiO 2 / 2 It has only the constituent units represented by ".

[0043] R 3This includes hydrogen atoms, alkyl groups, alkenyl groups, alkynyl groups, aralkyl groups, aryl groups, and -C(=O)-CR groups. 2 At least one selected from the group consisting of the group represented by 3, or a monovalent organic group (polymerizable functional group) having a reactive group. If n is 2 or more, there are multiple R 3 They may be the same or they may be different.

[0044] Alkyl group, alkenyl group, alkynyl group, aralkyl group, aryl group, -C(=O)-CR 3 3. Regarding preferred embodiments of polymerizable functional groups, etc., the formula "R 1 The same configurations as those described in the various embodiments of "[ ]" can be cited.

[0045] The number of structures represented by formula 2 (i.e., the number of n) in dimethylorganopolysiloxane (type D) is a positive integer.

[0046] ·Content ratio (T type / D type) The content ratio (Type T / Type D) of organopolysiloxane (Type T) and dimethylorganopolysiloxane (Type D) in the specific composition is 1 / 9 or more and 9 / 1 or less. A content ratio (Type T / Type D) of 1 / 9 or more enhances the release properties from the toner on the surface layer, resulting in high fixation performance. A content ratio (Type T / Type D) of 9 / 1 or less enhances the flexibility of the surface layer, improving the ability of the fixing member to conform to the recesses of the recording medium having irregularities, thus resulting in high fixation performance even when using toner containing a large amount of fine toner particles. From the viewpoint of further improving fixation performance, a content ratio (Type T / Type D) of 3 / 7 or more and 7 / 3 or less is preferable.

[0047] This document describes a method for detecting the content ratio of organopolysiloxane (Type T) and dimethylorganopolysiloxane (Type D) in a specific composition from the surface layer, which is the cured product of the specific composition. The content ratio is calculated by measuring the content of organopolysiloxane (Type T) and dimethylorganopolysiloxane (Type D) in the surface layer by infrared absorption spectroscopy (IR) analysis.

[0048] • Surface layer: Other additives The surface layer may contain other additives besides organopolysiloxane (Type T) and dimethylorganopolysiloxane (Type D). Examples of other additives include conductive particles (e.g., carbon black), low-friction particles (e.g., graphite), molybdenum disulfide, and silica particles. The content of each additive may be, for example, 1% to 5% by mass for conductive particles, 1% to 10% by mass for low-friction particles, and 1% to 20% by mass for silica particles. When the surface layer contains other additives, the total amount of organopolysiloxane (Type T) and dimethylorganopolysiloxane (Type D) in the surface layer is preferably 60% by mass or more, and more preferably 80% by mass. The total amount of organopolysiloxane (Type T) and dimethylorganopolysiloxane (Type D) in the surface layer may be 100% by mass (i.e., without other additives).

[0049] • The difference between the maximum and minimum values ​​of ultramicrohardness ΔH The surface layer has a difference ΔH between the maximum and minimum ultra-microhardness values ​​measured at 50 arbitrary points using the ultra-microhardness test specified in JIS Z2255 (2003), which is between 0% and 50%. A difference ΔH of less than or equal to the above upper limit indicates that organopolysiloxane (T-type) and dimethylorganopolysiloxane (D-type) are dispersed in the surface layer, and unevenness between the two is suppressed. Therefore, by having a difference ΔH of less than or equal to the above upper limit, the surface layer is made more flexible while ensuring release properties from the toner. As a result, even when using recording media with uneven surfaces, the ability of the fixing member to follow the recesses is improved, and high fixing performance can be obtained even when using toner containing a large amount of fine toner particles. From the viewpoint of further improving fixing performance, it is preferable that the above difference ΔH of the surface layer be between 0% and 40%.

[0050] From the viewpoint of controlling the difference ΔH between the maximum and minimum values ​​of ultrafine hardness to the above range, it is preferable to use compounds of organopolysiloxane (T-type) and dimethylorganopolysiloxane (D-type) that are in solution state at room temperature (i.e., 25°C). Furthermore, it is preferable to use a combination of highly compatible materials for organopolysiloxane (T-type) and dimethylorganopolysiloxane (D-type) so that they disperse well when kneaded.

[0051] • Tensile elongation The surface layer preferably has a tensile elongation of 50% or more, and more preferably 70% or more. While there is no particular upper limit to the tensile elongation of the surface layer, it is preferably, for example, 300%. By having the lower limit of the tensile elongation within the above range, the surface layer maintains strength while increasing flexibility, resulting in high adhesion.

[0052] The method for measuring the tensile elongation of the surface layer is as follows: Using a tensile testing machine (MODEL-1605N, manufactured by Aiko Engineering Co., Ltd.), a piece of 80 mm x 5 mm is cut out so that the circumferential direction of the surface layer is the longer side. The test is then conducted with a test piece length of 40 mm between the chuck fixtures at a tensile speed of 20 mm / min, and the tensile elongation is calculated.

[0053] To control the tensile elongation within the above range, it is preferable that the surface layer contains a dispersion of organopolysiloxane (T-type) and dimethylorganopolysiloxane (D-type), with unevenness between the two suppressed. Therefore, it is preferable to use compounds of both organopolysiloxane (T-type) and dimethylorganopolysiloxane (D-type) that are in solution at room temperature (i.e., 25°C). Furthermore, it is preferable to use a combination of highly compatible materials for organopolysiloxane (T-type) and dimethylorganopolysiloxane (D-type) so that they disperse well when kneaded.

[0054] • Surface roughness of the surface layer The surface roughness Ra of the outer surface of the surface layer, that is, the surface that comes into contact with the toner image, is preferably 1 μm or less, and more preferably 0.5 μm or less. Having a surface roughness Ra within this range improves adhesion.

[0055] The surface roughness Ra is determined as follows: A sample is cut from the surface layer (or a fixing member having a surface layer). The Ra is measured on the sample using a stylus-type surface roughness measuring instrument (e.g., Surfcom 1400A: manufactured by Tokyo Seimitsu Co., Ltd.). The measurement conditions are in accordance with JIS B0601-1994, with an evaluation length Ln = 2.5 mm, a reference length L = 0.8 mm, and a cutoff value of 0.008 mm.

[0056] • Method for forming a surface layer As a method for forming the surface layer, for example, a specific composition is first prepared by mixing liquid organopolysiloxane (Type T) and liquid dimethylorganopolysiloxane (Type D). The obtained specific composition is then coated by immersing a cylindrical mold on which the base material of the fixing member is installed, and curing, thereby forming a surface layer on the base material.

[0057] (Base material and elastic layer) The fixing member has at least a surface layer and may further have a base material. Furthermore, the fixing member may have an elastic layer between the base material and the surface layer.

[0058] The fixing member according to this embodiment will be described below with reference to Figure 1. Figure 1 is a schematic cross-sectional view showing an example of a fixing member according to this embodiment. The fixing member 110 shown in Figure 1 comprises a base layer 110A, an elastic layer 110B provided on the base layer 110A, and a surface layer 110C provided on the elastic layer 110B.

[0059] The layer configuration of the fixing member 110 according to this embodiment is not limited to the layer configuration shown in Figure 1, and it may not have an elastic layer 110B, nor may it have a base layer 110A. The layer configuration of the fixing member 110 according to this embodiment may be a layer configuration in which a metal layer and its protective layer are interposed between the base layer 110A and the elastic layer 110B, a layer configuration in which an adhesive layer is interposed between the base layer 110A and the elastic layer 110B, a layer configuration in which an adhesive layer is interposed between the elastic layer 110B and the surface layer 110C, or a layer configuration that combines these layer configurations.

[0060] The components of the fixing member according to this embodiment will be described in detail below. Reference numerals will be omitted in the description.

[0061] ·Base material layer Examples of the base layer include a resin layer containing a resin such as polyimide. The resin may also contain additives such as fillers.

[0062] Examples of polyimides include imidized polyamic acid (a precursor of polyimide), which is a polymer of tetracarboxylic dianhydride and a diamine compound. Specifically, examples of polyimides include resins obtained by polymerizing equimolar amounts of tetracarboxylic dianhydride and a diamine compound in a solvent to obtain a solution of polyamic acid, and then imidizing that polyamic acid.

[0063] Examples of tetracarboxylic dianhydrides include both aromatic and aliphatic compounds, but from the viewpoint of heat resistance, aromatic compounds are preferred.

[0064] Examples of aromatic tetracarboxylic dianhydrides include pyromellitic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-biphenylsulfone tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 3,3',4,4'-biphenyl ether tetracarboxylic dianhydride, 3,3',4,4'-dimethyldiphenylsilane tetracarboxylic dianhydride, 3,3',4,4'-tetraphenylsilane tetracarboxylic dianhydride, 1,2,3,4-furan tetracarboxylic dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenyl sulfide dianhydride, 4,4 Examples include '-bis(3,4-dicarboxyphenoxy)diphenylsulfone dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenylpropane dianhydride, 3,3',4,4'-perfluoroisopropylidene diphthalic acid dianhydride, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, 2,3,3',4'-biphenyltetracarboxylic acid dianhydride, bis(phthalic acid)phenylphosphine oxide dianhydride, p-phenylene-bis(triphenylphthalic acid) dianhydride, m-phenylene-bis(triphenylphthalic acid) dianhydride, bis(triphenylphthalic acid)-4,4'-diphenyl ether dianhydride, and bis(triphenylphthalic acid)-4,4'-diphenylmethane dianhydride.

[0065] Examples of aliphatic tetracarboxylic dianhydrides include butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 3,5,6-tricarboxynorbonane-2-acetic acid dianhydride, 2,3,4,5-tetrahydrofurantetracarboxylic dianhydride, 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic acid dianhydride, and bicyclo[2,2,2]-octo-7-e Examples include aliphatic or alicyclic tetracarboxylic dianhydrides such as n-2,3,5,6-tetracarboxylic dianhydrides; and aliphatic tetracarboxylic dianhydrides having aromatic rings such as 1,3,3a,4,5,9b-hexahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-c]furan-1,3-dione, 1,3,3a,4,5,9b-hexahydro-5-methyl-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-c]furan-1,3-dione, and 1,3,3a,4,5,9b-hexahydro-8-methyl-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-c]furan-1,3-dione.

[0066] Among these, aromatic tetracarboxylic dianhydrides are particularly well-suited as tetracarboxylic dianhydrides. Specifically, for example, pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,3,3',4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-biphenylether tetracarboxylic dianhydride, and 3,3',4,4'-benzophenone tetracarboxylic dianhydride are well-suited. Furthermore, pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, and 3,3',4,4'-benzophenone tetracarboxylic dianhydride are particularly well-suited, especially 3,3',4,4'-bi Phenylate tetracarboxylic dianhydride is a good choice.

[0067] Furthermore, tetracarboxylic dianhydrides may be used individually or in combination of two or more types. Furthermore, when using two or more tetracarboxylic dianhydrides in combination, aromatic tetracarboxylic dianhydrides or aliphatic tetracarboxylic dianhydrides may be used individually, or aromatic tetracarboxylic dianhydrides and aliphatic tetracarboxylic dianhydrides may be used in combination.

[0068] On the other hand, diamine compounds are diamine compounds that have two amino groups in their molecular structure. Diamine compounds can be either aromatic or aliphatic compounds, but aromatic compounds are preferred.

[0069] Examples of diamine compounds include p-phenylenediamine, m-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 1,5-diaminonaphthalene, 3,3-dimethyl-4,4'-diaminobiphenyl, 5-amino-1-(4'-aminophenyl)-1,3,3-trimethylindan, and 6-amino-1-(4'-aminophenyl)-1,3 ,3-trimethylindan, 4,4'-diaminobenzanilide, 3,5-diamino-3'-trifluoromethylbenzanilide, 3,5-diamino-4'-trifluoromethylbenzanilide, 3,4'-diaminodiphenyl ether, 2,7-diaminofluorene, 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'-methylene-bis(2-chloroaniline), 2,2',5,5'-tetrachloro-4,4'-diaminobiphenyl, 2,2'-dichloro-4,4'-diamino-5,5'-dimethyl Toxybiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)-biphenyl, 1,3'-bis(4-aminophenoxy)benzene, 9,9-bis(4-aminophenyl)fluorene Aromatic diamines such as 4,4'-(p-phenyleneisopropylidene)bisaniline, 4,4'-(m-phenyleneisopropylidene)bisaniline, 2,2'-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]hexafluoropropane, and 4,4'-bis[4-(4-amino-2-trifluoromethyl)phenoxy]-octafluorobiphenyl; aromatic diamines such as diaminotetraphenylthiophene having two amino groups bonded to an aromatic ring and heteroatoms other than the nitrogen atom of the amino groups;1,1-Metaxylylenediamine, 1,3-Propanediamine, Tetramethylenediamine, Pentamethylenediamine, Octamethylenediamine, Nonameethylenediamine, 4,4-Diaminoheptamethylenediamine, 1,4-Diaminocyclohexane, Isophoronediamine, Tetrahydrodicyclopentadienylenediamine, Hexahydro-4,7-Methanoindanidinemethylenediamine, Tricyclo[6,2,1,0; 2.7 Examples include aliphatic diamines such as ]-undecylendimethyldiamine and 4,4'-methylenebis(cyclohexylamine), as well as alicyclic diamines.

[0070] Among these, aromatic diamine compounds are particularly good as diamine compounds. Specifically, for example, p-phenylenediamine, m-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfide, and 4,4'-diaminodiphenyl sulfone are good, with 4,4'-diaminodiphenyl ether and p-phenylenediamine being particularly good.

[0071] Furthermore, the diamine compounds may be used individually or in combination of two or more. Furthermore, when using two or more diamine compounds in combination, aromatic diamine compounds or aliphatic diamine compounds may be used individually, or aromatic diamine compounds and aliphatic diamine compounds may be used in combination.

[0072] Among these, from the viewpoint of heat resistance, aromatic polyimides (specifically, imidides of polyamic acids (precursors of polyimides), which are polymers of aromatic tetracarboxylic dianhydrides and aromatic diamine compounds) are preferred as polyimides. Furthermore, it is more preferable that the aromatic polyimide is a polyimide having a structural unit represented by the following general formula (PI1).

[0073] [ka]

[0074] In the general formula (PI1), RP1 represents a phenyl group or a biphenyl group, and RP2 represents a divalent aromatic group. Examples of divalent aromatic groups represented by RP2 include phenylene groups, naphthyl groups, biphenyl groups, and diphenyl ether groups. From the viewpoint of bending durability, phenylene groups and biphenyl groups are preferred as divalent aromatic groups.

[0075] The number-average molecular weight of polyimide is preferably 5,000 to 100,000, more preferably 7,000 to 50,000, and even more preferably 10,000 to 30,000.

[0076] The number-average molecular weight of polyimide is measured by gel permeation chromatography (GPC) under the following measurement conditions. • Column: Tosoh TSKgelα-M (7.8mm ID x 30cm) • Eluent: DMF (dimethylformamide) / 30 mM iBr / 60 mM phosphoric acid ·Flow rate: 0.6mL / min ·Injection volume: 60μL • Detector: RI (Differential Refractive Index Detector)

[0077] Examples of fillers include carbon materials such as acetylene black, graphite, graphitized carbon black, and ungraphitized carbon black; and metal nitrides such as aluminum nitride, silicon nitride, boron nitride, cerium oxide, and magnesium carbonate.

[0078] The substrate layer may further contain other additives besides the polyimide and filler mentioned above. Examples of other additives include softeners (paraffin-based, etc.), processing aids (stearic acid, etc.), antioxidants (amine-based, etc.), and vulcanizing agents (sulfur, metal oxides, peroxides, etc.).

[0079] The thickness of the substrate layer is preferably 30 μm to 200 μm, and particularly preferably 50 μm to 150 μm, from the viewpoint of thermal conductivity and mechanical strength.

[0080] The base layer is obtained by preparing a coating solution for forming the base layer containing polyimide (which may also contain additives such as fillers), applying the coating solution for forming the base layer onto a cylindrical mold, and drying it.

[0081] • Elastic layer The elastic layer contains an elastic material. In addition to the elastic material, the elastic layer may also contain well-known additives.

[0082] Examples of elastic materials include fluororesins, silicone resins, silicone rubber, fluororubber, and fluorosilicone rubber. Among these, silicone rubber and fluororubber are preferred as elastic materials from the viewpoint of heat resistance, thermal conductivity, and insulation, with silicone rubber being more preferred.

[0083] Examples of silicone rubber include RTV silicone rubber, HTV silicone rubber, and liquid silicone rubber. Specifically, examples include polydimethyl silicone rubber (MQ), methyl vinyl silicone rubber (VMQ), methylphenyl silicone rubber (PMQ), and fluorosilicone rubber (FVMQ).

[0084] As for the silicone rubber, those with an addition reaction type as the crosslinking mechanism are preferred. Furthermore, various types of functional groups are known for silicone rubber, and dimethyl silicone rubber having methyl groups, methylphenyl silicone rubber having methyl and phenyl groups, and vinyl silicone rubber having vinyl groups (vinyl group-containing silicone rubber) are preferred. Furthermore, as the silicone rubber, vinyl silicone rubber having vinyl groups is more preferred, and silicone rubber having an organopolysiloxane structure having vinyl groups and a hydrogen organopolysiloxane structure having hydrogen atoms (SiH) bonded to silicon atoms is even more preferred.

[0085] Examples of fluororubbers include vinylidene fluoride rubber, tetrafluoroethylene / propylene rubber, tetrafluoroethylene / perfluoromethyl vinyl ether rubber, phosphophazene rubber, and fluoropolyether.

[0086] The elastic material preferably has silicone rubber as its main component (i.e., contains 50% or more by mass of silicone rubber relative to the total mass of the elastic material). The silicone rubber content is more preferably 90% by mass or more, even more preferably 99% by mass or more, and may be 100% by mass, based on the total mass of the elastic material used in the elastic layer (1).

[0087] Possible additives in the elastic layer include fillers, softeners (paraffin-based, etc.), processing aids (stearic acid, etc.), antioxidants (amine-based, etc.), and vulcanizing agents (sulfur, metal oxides, peroxides, etc.). It may contain additives such as the following.

[0088] The elastic layer can be formed by applying known methods, such as a coating method. When using silicone rubber as the elastic material for the elastic layer, for example, first, a coating solution for forming the elastic layer is prepared, which contains liquid silicone rubber that hardens into silicone rubber upon heating. Next, the coating solution for forming the elastic layer is applied to the substrate layer to form a coating film, and the coating film is vulcanized as needed to form an elastic layer on the substrate layer. In the vulcanization of the coating film, for example, the vulcanization temperature is 150°C to 250°C, and the vulcanization time is 30 minutes to 120 minutes.

[0089] • Film thickness of the surface layer and elastic layer Preferably, the fixing member has an elastic layer and a surface layer on the elastic layer, with an average film thickness of 30 μm or less for the surface layer and an average film thickness of 300 μm or more for the elastic layer. More preferably, the average film thickness of the surface layer is 10 μm or more and 50 μm or less, and the average film thickness of the elastic layer is 150 μm or more and 600 μm or less. For fixing to paper with irregularities, it is preferable that the surface of the fixing member conforms to the recesses of the paper as deeply as possible, and the conformability and fixing performance are enhanced when the film thicknesses of the surface layer and elastic layer are within the above ranges.

[0090] [Developer] The electrostatic image developer contains toner in which the number percentage of toner particles with a particle size of 4 μm or less is 15% or more. Examples of toners containing a large amount of fine powdery toner particles (i.e., toner particles with a particle size of 4 μm or less) include toners that have been made smaller in diameter to meet requirements such as improving the image quality of toner images. Examples of toners that have been made smaller in diameter include toners in which the volume average particle size (D50v) of the toner particles is 2 μm or more and 10 μm or less (more preferably 4 μm or more and 8 μm or less). The percentage of toner particles with a particle size of 4 μm or less may be 20% or more, 25% or more, or 30% or more. The higher the percentage of toner particles with a particle size of 4 μm or less, the worse the adhesion to paper with uneven surfaces. On the other hand, since smaller particle sizes result in lower electrostatic properties and an increase in waste toner because the toner is not transferred to the paper, the percentage of toner particles with a particle size of 4 μm or less may be 50% or less.

[0091] (Various average particle sizes and various particle size distribution indices) The average particle size and particle size distribution indices of toner particles are measured using a Coulter Multisizer 4e (manufactured by Beckman Coulter), and the electrolyte is measured using an ISOTON-II (manufactured by Beckman Coulter). For measurement, add 0.5 mg to 50 mg of the sample to be measured in 2 ml of a 5% aqueous solution of a surfactant (preferably sodium alkylbenzenesulfonate) as a dispersant. Add this to 100 ml to 150 ml of electrolyte. The electrolyte containing the suspended sample is dispersed in an ultrasonic disperser for 1 minute. The particle size distribution of particles with a diameter of 1 μm to 30 μm is then measured using a Coulter Multisizer 4e with a 50 μm aperture. The number of particles sampled is 50,000. Based on the measured particle size distribution, a cumulative distribution of volume and number is drawn for each divided particle size range (channel) from the smallest diameter side. The particle size at which the cumulative total reaches 16% is defined as the volume particle size D16v and the number particle size D16p, the particle size at which the cumulative total reaches 50% is defined as the volume average particle size D50v and the cumulative number average particle size D50p, and the particle size at which the cumulative total reaches 84% ​​is defined as the volume particle size D84v and the number particle size D84p. Using these, the volume particle size distribution index (GSDv) is (D84v / D16v) 1 / 2 The GSDp index is (D84p / D16p) 1 / 2 It is calculated as follows. The percentage of toner particles with a particle size of 4 μm or less is also calculated from this measurement. From the particle size distribution of the measured toner particles, the percentage of toner particles with a particle size of 4 μm or less is determined out of the 50,000 particles measured.

[0092] (Toner particles) The toner particles may include, for example, a binder resin, a colorant, a release agent, internal resin particles, and other additives.

[0093] -Binding resin- Examples of binder resins include vinyl resins consisting of monomers such as styrenes (e.g., styrene, parachlorostyrene, α-methylstyrene, etc.), (meth)acrylic acid esters (e.g., methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, etc.), ethylenically unsaturated nitriles (e.g., acrylonitrile, methacrylonitrile, etc.), vinyl ethers (e.g., vinyl methyl ether, vinyl isobutyl ether, etc.), vinyl ketones (vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone, etc.), and olefins (e.g., ethylene, propylene, butadiene, etc.), or copolymers of two or more of these monomers. Examples of binder resins include non-vinyl resins such as epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, and modified rosin; mixtures of these with the aforementioned vinyl resins; and graft polymers obtained by polymerizing vinyl monomers in the presence of these. These binding resins may be used individually or in combination of two or more types.

[0094] Polyester resin is preferred as the binder resin. Examples of polyester resins include known polyester resins. The polyester resin may be amorphous or crystalline. However, the crystalline polyester resin should be used in an amount of 2% to 40% by mass (preferably 2% to 30% by mass) relative to the total binding resin.

[0095] Furthermore, the "crystalline nature" of a resin refers to the presence of a clear endothermic peak rather than a stepwise change in endothermic quantity in differential scanning calorimetry (DSC). Specifically, it means that the full width at half maximum of the endothermic peak measured at a heating rate of 10°C / min is within 10°C. On the other hand, "amorphous" resins refer to those with a full width at half maximum exceeding 10°C, exhibiting a stepwise change in endothermic capacity, or lacking a clear endothermic peak.

[0096] Examples of amorphous polyester resins include condensation polymers of polycarboxylic acids and polyhydric alcohols. The amorphous polyester resin may be a commercially available product or a synthesized one.

[0097] Examples of polycarboxylic acids include aliphatic dicarboxylic acids (e.g., oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, alkenylsuccinic acid, adipic acid, sebacic acid, etc.), alicyclic dicarboxylic acids (e.g., cyclohexanedicarboxylic acid, etc.), aromatic dicarboxylic acids (e.g., terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, etc.), their anhydrides, or their lower alkyl esters (e.g., with 1 to 5 carbon atoms). Among these, aromatic dicarboxylic acids are preferred as polycarboxylic acids. Polycarboxylic acids may be used in combination with dicarboxylic acids, or with trivalent or higher carboxylic acids that have a cross-linked or branched structure. Examples of trivalent or higher carboxylic acids include trimellitic acid, pyromellitic acid, their anhydrides, or their lower alkyl esters (e.g., having 1 to 5 carbon atoms). Polycarboxylic acids may be used individually or in combination of two or more.

[0098] Examples of polyhydric alcohols include aliphatic diols (e.g., ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, etc.), alicyclic diols (e.g., cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A, etc.), and aromatic diols (e.g., ethylene oxide adducts of bisphenol A, propylene oxide adducts of bisphenol A, etc.). Among these, aromatic diols and alicyclic diols are preferred as polyhydric alcohols, and aromatic diols are more preferred. As for the polyhydric alcohol, a trihydric or higher polyhydric alcohol with a cross-linked or branched structure may be used in combination with the diol. Examples of trihydric or higher polyhydric alcohols include glycerin, trimethylolpropane, and pentaerythritol. Polyhydric alcohols may be used individually or in combination of two or more types.

[0099] The glass transition temperature (Tg) of amorphous polyester resin is preferably 50°C to 80°C, and more preferably 50°C to 65°C. The glass transition temperature is determined from the DSC curve obtained by differential scanning calorimetry (DSC), and more specifically, it is determined by the "extracorporeal glass transition onset temperature" described in the method for determining the glass transition temperature in JIS K 7121-1987 "Method for Measuring the Transition Temperature of Plastics".

[0100] The weight-average molecular weight (Mw) of the amorphous polyester resin is preferably 5,000 to 1,000,000, and more preferably 7,000 to 500,000. The number-average molecular weight (Mn) of the amorphous polyester resin is preferably between 2,000 and 100,000. The molecular weight distribution (Mw / Mn) of the amorphous polyester resin is preferably 1.5 to 100, and more preferably 2 to 60. The weight-average molecular weight and number-average molecular weight are measured by gel permeation chromatography (GPC). GPC molecular weight measurement is performed using a Tosoh GPC-HLC-8120GPC analyzer, a Tosoh TSKgel SuperHM-M (15cm) column, and THF solvent. The weight-average molecular weight and number-average molecular weight are calculated from these measurement results using a molecular weight calibration curve prepared with monodisperse polystyrene standard samples. Amorphous polyesters may be used individually or in combination of two or more types. When using two or more types in combination, for example, a high molecular weight and a low molecular weight polyester may be used together.

[0101] Amorphous polyester resins can be obtained by well-known manufacturing methods. Specifically, for example, they can be obtained by a method in which the polymerization temperature is set to 180°C or higher and 230°C or lower, and the reaction system is subjected to reduced pressure as needed, while removing water and alcohol generated during condensation.

[0102] Furthermore, the amorphous polyester resin may be a hybrid resin having a polyester resin segment and a styrene-acrylic copolymer segment.

[0103] Crystalline polyester resins include, for example, polycondensates of polycarboxylic acids and polyhydric alcohols. Commercially available crystalline polyester resins may be used, or synthesized resins may be used. Here, in order to easily form a crystalline structure, polycondensates using polymerizable monomers having linear aliphatic structures are preferred over polymerizable monomers having aromatic structures.

[0104] Examples of polycarboxylic acids include aliphatic dicarboxylic acids (e.g., oxalic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, etc.), aromatic dicarboxylic acids (e.g., phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid, etc.), their anhydrides, or their lower alkyl esters (e.g., having 1 to 5 carbon atoms). Polycarboxylic acids may be used in combination with dicarboxylic acids, or with trivalent or higher carboxylic acids that have a crosslinked or branched structure. Examples of trivalent or higher carboxylic acids include trimellitic acid, pyromellitic acid, their anhydrides, or their lower alkyl esters (e.g., having 1 to 5 carbon atoms). In addition to these dicarboxylic acids, polycarboxylic acids with sulfonic acid groups and dicarboxylic acids with ethylenic double bonds may also be used in combination. Polycarboxylic acids may be used individually or in combination of two or more.

[0105] Examples of polyhydric alcohols include aliphatic diols (for example, linear aliphatic diols in which the main chain has 2 to 20 carbon atoms). Examples of aliphatic diols include ethylene glycol, 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, and 1,20-icosanediol. Among these, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferred as aliphatic diols. Polyhydric alcohols may be used in combination with diols, including trihydric or higher alcohols that have a cross-linked or branched structure. Examples of trihydric or higher alcohols include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol. Polyhydric alcohols may be used individually or in combination of two or more types. Here, the polyhydric alcohol is preferably composed of 80 mol% or more of aliphatic diols, and more preferably 90 mol% or more.

[0106] The melting temperature of the crystalline polyester resin is preferably 50°C to 100°C, more preferably 55°C to 90°C, and even more preferably 60°C to 85°C. The melting temperature is determined from the DSC curve obtained by differential scanning calorimetry (DSC) using the "melting peak temperature" described in JIS K7121-1987 "Method for determining the transition temperature of plastics".

[0107] The weight-average molecular weight (Mw) of the crystalline polyester resin is preferably between 6,000 and 50,000.

[0108] Crystalline polyester resins can be obtained, for example, by well-known manufacturing methods, similar to amorphous polyesters.

[0109] The binder resin content is preferably 40% to 95% by mass, more preferably 50% to 90% by mass, and even more preferably 60% to 90% by mass, relative to the total toner particles.

[0110] -Coloring agent- Examples of colorants include carbon black, chrome yellow, Hansa yellow, benzidine yellow, surene yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, balkan orange, Watch Young red, permanent red, brilliant carmine 3B, brilliant carmine 6B, DuPont oil red, pyrazolone red, risole red, rhodamine B lake, lake red C, pigment red, rose bengal, aniline blue, ultramarine blue, and calco oil blue. Examples include various pigments such as methylene blue chloride, phthalocyanine blue, pigment blue, phthalocyanine green, and malachite green oxalate; inorganic pigments such as titanium compounds, silica, aluminum, and mica; and various dyes such as acridine, xanthene, azo, benzoquinone, azine, anthraquinone, thioindigo, dioxazine, thiazine, azomethine, indigo, phthalocyanine, aniline black, polymethine, triphenylmethane, diphenylmethane, and thiazole. The colorant is not limited to substances that absorb in the visible light region. For example, the colorant may be a substance that absorbs in the near-infrared region, a fluorescent colorant, or a colorant that exhibits luminescence. Colorants may be used individually or in combination of two or more types.

[0111] The coloring agent may be a surface-treated coloring agent as needed, and may be used in combination with a dispersant. Furthermore, multiple types of coloring agents may be used in combination.

[0112] The colorant content is preferably 1% to 30% by mass, and more preferably 3% to 15% by mass, relative to the total toner particles.

[0113] -Release agent- Examples of release agents include hydrocarbon waxes; natural waxes such as carnauba wax, rice wax, and candelilla wax; synthetic or mineral / petroleum-based waxes such as montan wax; and ester waxes such as fatty acid esters and montanic acid esters. Paraffin wax is preferred as a release agent.

[0114] The melting temperature of the release agent is preferably 50°C to 110°C, more preferably 60°C to 100°C, and even more preferably 75°C to 95°C. The melting temperature is determined from the DSC curve obtained by differential scanning calorimetry (DSC) using the "melting peak temperature" described in JIS K 7121-1987 "Method for determining the transition temperature of plastics".

[0115] The release agent content is preferably 1% to 20% by mass, and more preferably 4% to 15% by mass, relative to the total toner particles.

[0116] -Internal resin particles- Examples of internally added resin particles other than the binder resin include polyolefin resins (polyethylene, polypropylene, etc.), styrene resins (polystyrene, α-polymethylstyrene, etc.), (meth)acrylic resins (polymethyl methacrylate, polyacrylonitrile, etc.), epoxy resins, polyurethane resins, polyurea resins, polyamide resins, polycarbonate resins, polyether resins, polyester resins, and copolymer resins thereof. Styrene-(meth)acrylic copolymer resin particles are preferred as the internally added resin particles.

[0117] Examples of styrene-(meth)acrylic copolymer resin particles include resin particles obtained by polymerizing styrene monomers and (meth)acrylic acid monomers by radical polymerization.

[0118] Examples of styrene monomers include styrene, α-methylstyrene, vinylnaphthalene, alkyl-substituted styrenes having alkyl chains such as 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, and 4-ethylstyrene, halogen-substituted styrenes such as 2-chlorostyrene, 3-chlorostyrene, and 4-chlorostyrene, and fluorine-substituted styrenes such as 4-fluorostyrene and 2,5-difluorostyrene. Among these, styrene and α-methylstyrene are preferred as styrene monomers.

[0119] Examples of (meth)acrylic acid monomers include (meth)acrylic acid, n-methyl (meth)acrylate, n-ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, n-lauryl (meth)acrylate, n-tetradecyl (meth)acrylate, n-hexadecyl (meth)acrylate, n-octadecyl (meth)acrylate, isopropyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, isopentyl (meth)acrylate, amyl (meth)acrylate, (meth)acrylate Examples of (meth)acrylic acid monomers include neopentyl acrylate, isohexyl methacrylate, isoheptyl methacrylate, isooctyl methacrylate, 2-ethylhexyl methacrylate, phenyl methacrylate, biphenyl methacrylate, diphenylethyl methacrylate, t-butylphenyl methacrylate, terphenyl methacrylate, cyclohexyl methacrylate, t-butylcyclohexyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, methoxyethyl methacrylate, 2-hydroxyethyl methacrylate, β-carboxyethyl methacrylate, acrylonitrile, and methacrylamide. Among these, n-butyl methacrylate and β-carboxyethyl methacrylate are preferred as (meth)acrylic acid monomers.

[0120] The internally added resin particles are preferably crosslinked resin particles. In crosslinked resin particles, the crosslinking agent for crosslinking the resin is, for example, aromatic polyhydric vinyl compounds such as divinylbenzene and divinylnaphthalene; polyhydric vinyl esters of aromatic polyhydric carboxylic acids such as divinyl phthalate, divinyl isophthalate, divinyl terephthalate, divinyl homophthalate, divinyl trimesicate, trivinyl trimesicate, divinyl naphthalenedicarboxylate, and divinyl biphenylcarboxylate; divinyl esters of nitrogen-containing aromatic compounds such as divinyl pyridinedicarboxylate; vinyl esters of unsaturated heterocyclic carboxylic acid compounds such as vinyl pyromutinate, vinyl furanate, vinyl pyrrole-2-carboxylate, and vinyl thiophenecarboxylate; butanediol dimethacrylate, hexa Examples include (meth)acrylic acid esters of linear polyhydric alcohols such as benzoyl diacrylate, hexanediol dimethacrylate, octanediolic diacrylate, octanediolic dimethacrylate, nonanediol diacrylate, nonanediol dimethacrylate, decanediolic diacrylate, decanediolic dimethacrylate, dodecanediol diacrylate, and dodecanediol dimethacrylate; (meth)acrylic acid esters of branched and substituted polyhydric alcohols such as neopentyl glycol dimethacrylate and 2-hydroxy, 1,3-diacryloxypropane; and polyethylene glycol di(meth)acrylate and polypropylene polyethylene glycol di(meth)acrylate. The crosslinking agent may be used alone or in combination of two or more types.

[0121] Examples of copolymer resin particles of a styrene monomer and a (meth)acrylic acid monomer include copolymer resin particles in which the styrene monomer is styrene, the (meth)acrylic acid monomer is n-butyl acrylate, and the mass ratio of the styrene monomer to the (meth)acrylic acid monomer (styrene monomer to (meth)acrylic acid monomer) is 70 / 30 or more and 10 / 90 or less (preferably 65 / 35 or more and 20 / 80 or less).

[0122] The average primary particle size of the internally added resin particles is preferably 50 nm to 500 nm, more preferably 20 nm to 300 nm, and even more preferably 30 nm to 250 nm. When the average primary particle size of the internally added resin particles is within the above range, the internally added resin particles are less likely to aggregate within the toner particles and tend to exist at an appropriate size.

[0123] The average primary particle size of the internally added resin particles is a value measured using a transmission electron microscope (TEM). For example, the JEM-2100plus manufactured by JEOL Ltd. is used as a transmission electron microscope. Specifically, the method for measuring the average primary particle size of the internally added resin particles is as follows: The toner particles are cut into pieces approximately 0.1 μm thick using a microtome. A 10,000x magnification image of the cross-section of the toner particles is taken using a transmission electron microscope. For 100 internal resin particles dispersed within the toner particles, the equivalent diameter of each circle is calculated from the individual cross-sectional area, and the arithmetic mean of these values ​​is used as the average primary particle size.

[0124] The content of internally added resin particles is preferably 2% to 30% by mass, more preferably 3% to 25% by mass, and even more preferably 5% to 20% by mass, relative to the toner particles.

[0125] -Other additives- Other additives include well-known additives such as magnetic materials, charge control agents, and inorganic powders. These additives are included in the toner particles as internal additives.

[0126] -Characteristics of toner particles, etc.- The toner particles may be single-layer toner particles, or they may be toner particles with a so-called core-shell structure, consisting of a core (core particle) and a coating layer (shell layer) that covers the core. Here, the core-shell structured toner particles may consist of, for example, a core made up of a binder resin and, if necessary, a colorant, a release agent, and other additives, and a coating layer made up of a binder resin, the coating layer may have a multilayer structure, and the type of binder resin, the presence or absence and type of colorant and release agent may be changed depending on the core and each coating layer.

[0127] From the viewpoint of achieving both fine line reproducibility and transfer efficiency, the volume-average particle size (D50v) of the toner particles is preferably 2 μm to 10 μm, and more preferably 4 μm to 8 μm.

[0128] The average circularity of the toner particles is preferably 0.90 or more and 1.00 or less, and more preferably 0.92 or more and 0.98 or less.

[0129] The average circularity of toner particles is determined by (circular equivalent perimeter) / (perimeter) [(perimeter of a circle with the same projected area as the particle image) / (perimeter of the particle projection image)]. Specifically, it is a value measured by the following method. First, the toner particles to be measured are collected by suction, a flattened flow is formed, and a strobe flash is instantaneously activated to capture a still image of the particles. This particle image is then analyzed using a flow-type particle image analyzer (Paasche analyzer PAS, manufactured by Hosokawa Micron Corporation). The number of samples used to determine the average circularity is 10,000. If the toner contains external additives, the toner (developer) to be measured is dispersed in water containing a surfactant, and then ultrasonic treatment is performed to obtain toner particles from which the external additives have been removed.

[0130] (External additive) Examples of external additives include inorganic particles. These inorganic particles include SiO2, TiO2, Al2O3, SrTiO3, CaTiO3, CuO, ZnO, SnO2, CeO2, Fe2O3, MgO, BaO, CaO, K2O, Na2O, ZrO2, CaO·SiO2, and K2O·(TiO2). n Examples include Al2O3·2SiO2, CaCO3, MgCO3, BaSO4, and MgSO4.

[0131] The surface of the inorganic particles used as an external additive should preferably be hydrophobic. Hydrophobic treatment is carried out, for example, by immersing the inorganic particles in a hydrophobic agent. The hydrophobic agent is not particularly limited, but examples include silane-based coupling agents, silicone oil, titanate-based coupling agents, and aluminum-based coupling agents. These may be used individually or in combination of two or more. The amount of hydrophobic treatment agent is typically, for example, 1 to 10 parts by mass per 100 parts by mass of inorganic particles.

[0132] Examples of external additives include resin particles (such as polystyrene, polymethyl methacrylate (PMMA), and melamine resin), and cleaning lubricants (for example, metal salts of higher fatty acids represented by zinc stearate, and particles of higher alcohols).

[0133] The volume-average particle size (primary particle diameter) of the external additive is preferably 1 nm to 500 nm, more preferably 10 nm to 400 nm, and even more preferably 20 nm to 200 nm, from the viewpoint of improving the fluidity of the toner particles.

[0134] The volume-average particle size of the external additive is measured using a laser diffraction particle size distribution analyzer (LA-700: manufactured by Horiba, Ltd.). The measurement method involves adjusting the sample, which is in dispersion form, to a solid content of 2 g, and then adding deionized water to make a total volume of 40 ml. This is then poured into a cell until the appropriate concentration is reached, and after waiting 2 minutes for the concentration in the cell to stabilize, the measurement is taken. The measured particle size distribution is then plotted as a cumulative distribution from the smallest diameter side for each divided particle size range (channel), and the particle size at which the cumulative volume reaches 50% is defined as the volume-average particle size. When measuring powders such as external additives, add 2 g of the sample to be measured to 50 ml of a 5% by mass aqueous solution of a surfactant (preferably sodium alkylbenzenesulfonate), disperse it in an ultrasonic disperser (1,000 Hz) for 2 minutes to prepare the sample, and measure it in the same manner as the dispersion described above.

[0135] From the viewpoint of improving the fluidity of toner particles, the amount of external additive added is preferably 2 to 10 parts by mass of the external additive as a whole, more preferably 3 to 7 parts by mass, and even more preferably 4 to 6 parts by mass, per 100 parts by mass of toner particles.

[0136] The amount of external additive added is preferably 0.01% by mass or more and 10% by mass or less relative to the toner particles, and more preferably 0.01% by mass or more and 6.0% by mass or less.

[0137] (Toner manufacturing method) Next, the toner manufacturing method used in this embodiment will be described. The toner used in this embodiment is obtained by manufacturing toner particles and then adding an external additive to the toner particles.

[0138] Toner particles may be manufactured by either a dry process (e.g., kneading and grinding method) or a wet process (e.g., agglomeration, suspension polymerization, dissolution and suspension method). There are no particular restrictions on the manufacturing method of toner particles, and any well-known method may be used.

[0139] Among these methods, the aggregation and coalescence method is preferred for reducing the diameter of toner particles and controlling the amount of fine toner particles. There are no particular restrictions on the method for controlling the number ratio of fine toner particles, i.e., toner particles with a particle size of 4 μm or less. For example, in the dry kneading and grinding method, this can be adjusted by grinding and classification, or in the wet method, by changing the amount of flocculant added or the solid content ratio in the first agglomerated particle formation step of the agglomeration and coalescence method. When using the kneading and grinding method, for example, after grinding the material mixture using a well-known method, the proportion of toner particles that are 4 μm or smaller can be adjusted by changing the classification edge position using an elbow jet classifier (manufactured by Matsubo Co., Ltd.) in the classification process. When using the agglomeration method, for example, increasing the amount of flocculant added in the first agglomeration step strengthens the flocculation force, thereby adjusting (reducing) the proportion of toner particles smaller than 4 μm. Alternatively, increasing the solid content in the first agglomeration step also adjusts (reduces) the proportion of toner particles smaller than 4 μm.

[0140] Specifically, for example, when manufacturing toner particles by an aggregation and coalescence method, for example, The process involves mixing a first resin particle dispersion containing first resin particles that will serve as a binder, a colorant dispersion containing a colorant, and a release agent particle dispersion containing release agent particles (hereinafter also referred to as "release agent particles"), and then agglomerating each particle and the colorant in the resulting dispersion to form first aggregated particles (first aggregated particle formation process). After obtaining a first aggregate particle dispersion in which the first aggregate particles are dispersed, a second resin particle, which will become a binder resin, is added to the first aggregate particle dispersion to aggregate the second resin particle on the surface of the first aggregate particles, thereby forming second aggregate particles (second aggregate particle formation step). The process involves heating the second aggregate particle dispersion, in which the second aggregate particles are dispersed, to fuse and combine the second aggregate particles and form toner particles (fusion and combination process), The toner particles are manufactured through this process. This aggregation and coalescence method is described as a method for producing toner particles containing a binder resin, a colorant, and a release agent; however, the colorant and release agent are components included in the toner particles as needed.

[0141] The details of each step are explained below.

[0142] -Each dispersion preparation process- First, prepare each dispersion used in the agglomeration method. Specifically, prepare a first resin particle dispersion containing first resin particles that will act as the binder, a colorant dispersion containing a colorant, a second resin particle dispersion containing second resin particles that will act as the binder, and a release agent particle dispersion containing release agent particles. In each dispersion preparation step, the first resin particles and the second resin particles will be referred to as "resin particles" in the explanation.

[0143] Here, the resin particle dispersion is prepared, for example, by dispersing resin particles in a dispersion medium with a surfactant.

[0144] Examples of dispersion media used in resin particle dispersions include aqueous media. Examples of aqueous media include water such as distilled water and deionized water, and alcohols. These may be used individually or in combination of two or more.

[0145] Examples of surfactants include anionic surfactants such as sulfate esters, sulfonates, phosphates, and soaps; cationic surfactants such as amine salts and quaternary ammonium salts; and nonionic surfactants such as polyethylene glycol, alkylphenol ethylene oxide adducts, and polyhydric alcohols. Among these, anionic surfactants and cationic surfactants are particularly noteworthy. Nonionic surfactants may be used in combination with anionic or cationic surfactants. Surfactants may be used individually or in combination of two or more types.

[0146] In resin particle dispersions, common dispersion methods for dispersing resin particles in a dispersion medium include, for example, rotary shear homogenizers, ball mills with media, sand mills, and dyno mills. Depending on the type of resin particles, the resin particles may also be dispersed in the resin particle dispersion using, for example, a phase inversion emulsification method. Phase inversion emulsification is a method in which the resin to be dispersed is dissolved in a hydrophobic organic solvent in which the resin is soluble, a base is added to the organic continuous phase (O phase) to neutralize it, and then an aqueous medium (W phase) is added. This causes a conversion of the resin from W / O to O / W (so-called phase inversion), resulting in a discontinuous phase, and the resin is dispersed in the aqueous medium in particulate form.

[0147] The volume-average particle size of the resin particles dispersed in the resin particle dispersion is preferably 0.01 μm or more and 1 μm or less, more preferably 0.03 μm or more and 0.8 μm or less, and even more preferably 0.05 μm or more and 0.6 μm or less. The volume-average particle size of the resin particles is measured using a laser diffraction particle size distribution analyzer (e.g., LA-960, manufactured by Horiba, Ltd.). The particle size distribution is obtained by subtracting the cumulative distribution from the smallest particle size side for each divided particle size range (channel), and the particle size that accounts for 50% of the total particle size is measured as the volume-average particle size D50v. The volume-average particle size of particles in other dispersions is measured in the same manner.

[0148] The resin particle content in the resin particle dispersion is preferably, for example, 5% by mass or more and 50% by mass or less, and more preferably 10% by mass or more and 40% by mass or less.

[0149] In addition, colorant dispersions and mold release agent particle dispersions are prepared in the same manner as the resin particle dispersions. That is, the volume average particle size, dispersion medium, dispersion method, and particle content of the resin particle dispersions are the same for the colorant dispersed in the colorant dispersion and the mold release agent particles dispersed in the mold release agent particle dispersion.

[0150] -First agglomerated particle formation process- Next, the first resin particle dispersion, the colorant dispersion, and the mold release agent particle dispersion are mixed together. Then, in this mixed dispersion, the first resin particles, colorant, and release agent particles are heteroaggregated to form first aggregated particles containing the first resin particles, colorant, and release agent particles.

[0151] Specifically, for example, a flocculant is added to a dispersion obtained by mixing a first resin particle dispersion, a colorant dispersion, and a mold release agent particle dispersion, and the pH of the mixed dispersion is adjusted to be acidic (for example, pH 2 to 5). After adding a dispersion stabilizer as needed, the temperature is set to a range of 20°C to 50°C to flocce the particles dispersed in the mixed dispersion and form first flocculated particles. In the first agglomerated particle formation step, for example, the mixed dispersion may be stirred with a rotary shear homogenizer, the above-mentioned flocculant may be added at room temperature (e.g., 25°C), the pH of the mixed dispersion may be adjusted to acidic (e.g., pH 2 to 5), a dispersion stabilizer may be added as needed, and then the above-mentioned heating may be performed.

[0152] Examples of flocculants include surfactants with opposite polarity to the surfactant used as a dispersant added to a mixed dispersion, inorganic metal salts, and metal complexes with a valency of 2 or higher. In particular, when a metal complex is used as a flocculant, the amount of surfactant used is reduced and the electrostatic properties are improved. Additives that form complexes or similar bonds with the metal ions of the flocculant may be used as needed. Chelating agents are preferably used as such additives.

[0153] Examples of inorganic metal salts include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate, as well as inorganic metal salt polymers such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. As a chelating agent, a water-soluble chelating agent may be used. Examples of chelating agents include oxycarboxylic acids such as tartaric acid, citric acid, and gluconic acid, as well as iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), and ethylenediaminetetraacetic acid (EDTA). The amount of chelating agent to be added is preferably 0.01 parts by mass or more and 5.0 parts by mass or less per 100 parts by mass of the first resin particles, and more preferably 0.1 parts by mass or more and less than 3.0 parts by mass. Furthermore, alkali may be added to adjust the pH of the system in order to control the effect of the chelating agent.

[0154] -Second agglomerated particle formation process- Next, after obtaining a first aggregate particle dispersion containing the first aggregate particles, a second resin particle dispersion containing the second resin particles is added to the first aggregate particle dispersion. The second resin particles may be of the same type as the first resin particles, or they may be of a different type.

[0155] Then, in a dispersion of first aggregated particles and second resin particles, the second resin particles are aggregated on the surface of the first aggregated particles. At this time, a release agent particle dispersion may also be added to aggregate the second resin particles and release agent particles on the surface of the first aggregated particles. Specifically, for example, in the first aggregated particle formation step, when the first aggregated particles reach the desired particle size, the second resin particle dispersion is added to the first aggregated particle dispersion, and heating is performed at a temperature below the glass transition temperature of the second resin particles. Then, by adjusting the pH of the dispersion to a range of, for example, between 6.5 and 8.5, the progression of aggregation is stopped. In this way, a second aggregated particle is obtained by agglomerating the first aggregated particle so that the second resin particle adheres to its surface.

[0156] -Fusion / unification process- Next, the second aggregate particle dispersion, in which the second aggregate particles are dispersed, is heated to a temperature above the glass transition temperature of the first and second resin particles (for example, 10 to 30°C higher than the glass transition temperature of the first and second resin particles) to fuse and combine the second aggregate particles and form toner particles. Additionally, the pH of the system may be adjusted by adding acid as needed to control the shape.

[0157] Toner particles are obtained through the above process. Furthermore, in the agglomeration and coalescence method described above, the second agglomeration particle formation step may be omitted, and the first agglomeration particles may be fused and coalesced to form toner particles. Alternatively, the second agglomeration particle formation step may be repeated multiple times, and the process may be repeated multiple times with changes in the type of binder resin, the presence or absence and type of colorant and release agent.

[0158] After the fusion and combination process is complete, the toner particles formed in the solution are subjected to known washing, solid-liquid separation, and drying processes to obtain dried toner particles. The washing process should be thoroughly performed using ion-exchanged water for displacement washing, considering the electrostatic charge. The solid-liquid separation process is not particularly restricted, but suction filtration, pressure filtration, etc., are preferable for productivity. The drying process is also not particularly restricted, but freeze-drying, air-flow drying, fluidized bed drying, vibratory fluidized bed drying, etc., are preferable for productivity.

[0159] The toner used in this embodiment is manufactured, for example, by adding an external additive to the obtained dried toner particles and mixing them. Mixing can be performed using, for example, a V-blender, a Henschel mixer, a Redigge mixer, etc. The external additive may be mixed with the toner particles all at once, or the external additive may be added to the toner particles in stages and mixed multiple times. Furthermore, if necessary, coarse particles of toner may be removed using a vibrating screen separator, a wind screen separator, etc.

[0160] <Electrostatic Image Developer> The electrostatic image developer used in this embodiment contains at least toner. The electrostatic image developer used in this embodiment may be a one-component developer containing only toner, or a two-component developer containing a mixture of toner and a carrier.

[0161] There are no particular restrictions on the carriers, and known carriers can be used. Examples of carriers include coated carriers in which a coating resin is applied to the surface of a core material made of magnetic powder; magnetic powder dispersed carriers in which magnetic powder is dispersed and blended in a matrix resin; and resin-impregnated carriers in which resin is impregnated into porous magnetic powder. Furthermore, magnetic powder dispersed carriers and resin-impregnated carriers may be carriers in which the constituent particles of the carrier are used as a core material and coated with a coating resin.

[0162] Examples of magnetic powders include magnetic metals such as iron, nickel, and cobalt, and magnetic oxides such as ferrite and magnetite. In particular, magnetite and ferrite are preferred as magnetic powders. The magnetic powder may also be used as particles in which the magnetic powder is dispersed in a resin.

[0163] Examples of coating resins and matrix resins include styrene-(meth)acrylic acid resin; polyolefin resins such as polyethylene resin and polypropylene resin; polyvinyl or polyvinylidene resins such as polystyrene, (meth)acrylic resin, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinylcarbazole, polyvinyl ether, and polyvinyl ketone; vinyl chloride-vinyl acetate copolymer; straight silicone resins or modified products thereof consisting of organosiloxane bonds; fluororesins such as polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, and polychlorotrifluoroethylene; polyester; polyurethane; polycarbonate; amino resins such as urea-formaldehyde resin; epoxy resin; and the like. The coating resin and matrix resin preferably contain a (meth)acrylic resin, and more preferably a (meth)acrylic resin having an alicyclic structure. The coating resin and matrix resin may also contain a nitrogen-containing (meth)acrylic resin. It is more preferable that the (meth)acrylic resin is present in an amount of 50% by mass or more relative to the total mass of the resin, and even more preferable that the (meth)acrylic resin is present in an amount of 80% by mass or more relative to the total mass of the resin. In particular, the coating resin and the matrix resin preferably contain an alicyclic (meth)acrylic resin as the (meth)acrylic resin. Furthermore, the coating resin and matrix resin may contain conductive particles or other additives. Examples of conductive particles include metals such as gold, silver, and copper, as well as carbon black, titanium oxide, zinc oxide, tin oxide, barium sulfate, aluminum borate, and potassium titanate. Other additives include metal oxide particles such as silica, titanium oxide, zinc oxide, and tin oxide; metal compound particles such as barium sulfate, aluminum borate, and potassium titanate; and metal particles such as gold, silver, and copper. Among these, silica particles are preferred. The above particles are preferably contained in an amount of 10% to 60% by mass relative to the total mass of the resin layer.

[0164] To coat the surface of the core material with a coating resin, one method is to coat it with a coating layer-forming solution in which the coating resin and, if necessary, various additives are dissolved in a suitable solvent. The solvent is not particularly limited and should be selected considering the coating resin used, its suitability for coating, etc. Specific resin coating methods include the immersion method, in which the core material is immersed in a coating layer forming solution; the spray method, in which the coating layer forming solution is sprayed onto the surface of the core material; the fluidized bed method, in which the coating layer forming solution is sprayed onto the core material while it is suspended by fluidized air; and the kneader coater method, in which the carrier core material and the coating layer forming solution are mixed in a kneader coater and the solvent is removed.

[0165] In a two-component developer, the mixing ratio (mass ratio) of toner and carrier is preferably toner:carrier = 1:100 to 30:100, and more preferably 3:100 to 20:100.

[0166] << Fixing device >> An example of a fixing device in this embodiment is one comprising a fixing member, a rotating body positioned in contact with the outer circumferential surface of the fixing member, and a pressing member positioned inside the fixing member and pressing the fixing member against the rotating body from the inner circumferential surface of the fixing member. The fixing member in this embodiment is used as the fixing member.

[0167] An example of a fixing device in this embodiment will be shown below with reference to the drawings.

[0168] (First embodiment of the fixing device) A first embodiment of the fixing device will be described with reference to Figure 2. Figure 2 is a schematic diagram showing an example of the first embodiment of the fixing device (i.e., fixing device 60).

[0169] As shown in Figure 2, the fixing device 60 is configured to include, for example, a rotating heating roll 61 (an example of a rotating body), a pressure belt 62 (an example of a fixing member), and a pressure pad 64 (an example of a pressing member) that presses the heating roll 61 via the pressure belt 62. The pressure pad 64 only needs to be relatively pressurized, for example, by the pressure belt 62 and the heating roll 61. Therefore, the pressure belt 62 may be pressed against the heating roll 61, or the heating roll 61 may be pressed against the pressure belt 62.

[0170] A halogen lamp 66 (an example of a heating device) is installed inside the heating roll 61. The heating means is not limited to a halogen lamp; other heat-generating components may also be used.

[0171] Meanwhile, a temperature-sensing element 69 is positioned in contact with the surface of the heating roll 61. Based on the temperature measured by this temperature-sensing element 69, the illumination of the halogen lamp 66 is controlled to maintain the surface temperature of the heating roll 61 at a target set temperature (for example, 170°C).

[0172] The pressure belt 62 is rotatably supported, for example, by an internally positioned pressure pad 64 and a belt travel guide 63. In the clamping region N (nip portion), it is pressed against the heating roll 61 by the pressure pad 64.

[0173] The pressure pad 64 is positioned, for example, inside the pressure belt 62, and is pressed against the heating roll 61 via the pressure belt 62, forming a clamping area N between it and the heating roll 61. The pressing pad 64 includes, for example, a front clamping member 64a positioned on the entrance side of the clamping area N to secure a wide clamping area N, and a peeling clamping member 64b positioned on the exit side of the clamping area N to impart distortion to the heating roll 61.

[0174] To reduce the sliding resistance between the inner circumferential surface of the pressure belt 62 and the pressure pad 64, for example, a sheet-like sliding member 68 is provided on the surfaces of the front clamping member 64a and the peeling clamping member 64b that are in contact with the pressure belt 62. The pressure pad 64 and the sliding member 68 are held together by a metal retaining member 65.

[0175] For example, a belt travel guide 63 is attached to the holding member 65, and the pressure belt 62 rotates within it.

[0176] The heating roll 61 rotates in the direction of arrow S by, for example, a drive motor (not shown), and the pressure belt 62 rotates in the direction of arrow R, opposite to the direction of rotation of the heating roll 61, in accordance with this rotation. That is, for example, while the heating roll 61 rotates clockwise in Figure 2, the pressure belt 62 rotates counterclockwise.

[0177] Then, the paper K (an example of a recording medium) having an unfixed toner image is guided, for example, by a fuser entrance guide 56 and transported to the sandwiching area N. As the paper K passes through the sandwiching area N, the unfixed toner image on the paper K is fixed by the pressure and heat acting on the sandwiching area N.

[0178] In the fixing device 60, for example, a concave front clamping member 64a that conforms to the outer surface of the heating roll 61 ensures a wider clamping area N compared to a configuration without the front clamping member 64a.

[0179] Furthermore, the fixing device 60 is configured such that, for example, the peeling and clamping member 64b is positioned to protrude from the outer surface of the heating roll 61, thereby increasing the localized distortion of the heating roll 61 in the exit region of the clamping region N.

[0180] By arranging the peeling and clamping member 64b in this manner, for example, when the fixed paper K passes through the peeling and clamping region, it will pass through a locally large amount of strain, making it easier for the paper K to peel off from the heating roll 61.

[0181] As an auxiliary means for peeling, for example, a peeling member 70 is disposed on the downstream side of the sandwiching region N of the heating roll 61. The peeling member 70 is held by a holding member 72, for example, in a state where peeling claws 71 are close to the heating roll 61 in a direction opposite to the rotation direction of the heating roll 61 (counter direction).

[0182] (Second Embodiment of Fixing Device) [[ID=⑧]]The second embodiment of the fixing device will be described with reference to FIG. 3. FIG. 3 is a schematic diagram showing an example of the second embodiment of the fixing device (that is, the fixing device 80). As shown in FIG. 3, the fixing device 80 includes, for example, a fixing belt module ⑧6 including a heating belt 84 (an example of a fixing member), and a pressure roll 88 (an example of a rotating body) disposed by pressing against the heating belt 84 (fixing belt module 86). And, for example, a sandwiching region N (nip portion) is formed at the contact portion between the heating belt 84 (fixing belt module 86) and the pressure roll 88. In the sandwiching region N, a sheet K (an example of a recording medium) is pressurized and heated, and the toner image is fixed.

[0183] The fixing belt module 86 includes, for example, an endless heating belt 84, a heating pressure roll 89 (an example of a pressing member) around which the heating belt 84 is wound on the pressure roll 88 side and is rotationally driven by the rotational force of a motor (not shown) and presses the heating belt 84 from its inner peripheral surface toward the pressure roll 88 side, and a support roll 90 that supports the heating belt 84 from the inside at a position different from the heating pressure roll 89.

[0184] The fixing belt module 86 is provided with, for example, a support roll 92 disposed outside the heating belt 84 and defining its circumferential path, a posture correction roll 94 that corrects the posture of the heating belt 84 from the heating pressure roll 89 to the support roll 90, and a support roll 98 that applies tension to the heating belt 84 from the inner peripheral surface on the downstream side of the sandwiching region N formed by the heating belt 84 and the pressure roll 88.

[0185] The fixing belt module 86 is provided such that, for example, a sheet-like sliding member 82 is interposed between the heating belt 84 and the heating pressure roll 89. The sliding member 82 is provided such that, for example, its sliding surface is in contact with the inner circumferential surface of the heating belt 84, and is involved in holding and supplying the oil present between it and the heating belt 84. Here, the sliding member 82 is provided such that, for example, both ends are supported by support members 96.

[0186] Inside the heated pressing roll 89, for example, a halogen heater 89A (an example of a heating device) is provided.

[0187] The support roll 90 is, for example, a cylindrical roll made of aluminum, and inside A halogen heater 90A (an example of a heating device) is installed to heat the heating belt 84 from the inner circumferential side. At both ends of the support roll 90, for example, spring members (not shown) are provided to press the heating belt 84 outwards. The support roll 92 is, for example, a cylindrical roll made of aluminum, and a release layer made of fluororesin with a thickness of 20 μm is formed on the surface of the support roll 92. The release layer on the support roll 92 is formed, for example, to prevent toner or paper dust from the outer surface of the heating belt 84 from accumulating on the support roll 92. Inside the support roll 92, for example, a halogen heater 92A (an example of a heating device) is provided to heat the heating belt 84 from the outer surface side. In other words, for example, the heating belt 84 is heated by the heating and pressing roll 89, the support roll 90, and the support roll 92.

[0188] The posture correction roll 94 is, for example, a cylindrical roll made of aluminum, and an end position measuring mechanism (not shown) for measuring the end position of the heating belt 84 is located near the posture correction roll 94.

[0189] The posture correction roll 94 is equipped with, for example, an axial displacement mechanism (not shown) that displaces the contact position of the heating belt 84 in the axial direction according to the measurement results of the end position measuring mechanism, and is configured to control the meandering of the heating belt 84.

[0190] On the other hand, the pressure roll 88 is, for example, rotatably supported and pressed against the portion of the heating belt 84 that is wound around the heating pressure roll 89 by a biasing device such as a spring (not shown). As a result, as the heating belt 84 (heating pressure roll 89) of the fixing belt module 86 rotates in the direction of arrow S, the pressure roll 88 rotates in the direction of arrow R, following the heating belt 84 (heating pressure roll 89).

[0191] The paper K, which has an unfixed toner image (not shown), is then transported in the direction of arrow P and guided to the clamping area N of the fixing device 80. As the paper K passes through the clamping area N, the unfixed toner image on the paper K is fixed by the pressure and heat acting on the clamping area N.

[0192] In the fixing device 80, a halogen heater (halogen lamp) was described as one example of a heating device, but the device is not limited to this. Other heating elements such as radiant lamps (heating elements that emit radiation (infrared rays, etc.)) and resistive heating elements (heating elements that generate Joule heat by passing an electric current through a resistor: for example, those made by forming a resistive film on a ceramic substrate and firing it) may also be used.

[0193] (Third embodiment of the fixing device) A third embodiment of the fixing device will be described with reference to Figure 4. Figure 4 is a schematic diagram showing an example of the third embodiment of the fixing device (i.e., fixing device 410). As shown in Figure 4, the fixing device 410 has a pressurizing section 414 and a heating section 430 facing the pressurizing section 414.

[0194] The pressurizing section 414 has a cylindrical roll member 412 (an example of a rotating body), is positioned opposite the heating section 430, and is pressed against the outer surface of the heating belt 432 of the heating section 430 and rotated by a drive device (not shown).

[0195] In the pressurized section 414, the roll member 412 is a so-called soft roll having a shaft portion 416 made of a metal material such as iron, stainless steel, or aluminum, an elastic layer 418 covering the shaft portion 416, and a release layer 420 coated or applied to the elastic layer 418. The release layer 420 is made of a material that is insulating and has excellent release properties, such as PFA.

[0196] In the pressurizing section 414, the roll member 412 is grounded, and the shaft portion 416 of the roll member 412 is grounded with the pressurizing section side resistor 422 in between. By grounding the pressurizing section 414 with the pressurizing section side resistor 422 in between in this way, current leakage (leakage current) from the electrodes of the planar heating element 440 of the heating section 430 is suppressed.

[0197] In the pressurizing section 414, the roll member 412 is pressed against the heating section 430 by a pressing member (not shown) made of an elastic material such as a coil spring. This pressing member is, for example, attached at one end to the shaft 416 and at the other end to the main body of the image forming apparatus.

[0198] The heating section 430 includes a heating belt 432 (an example of a fixing member), a planar heating element 440 located inside the heating belt 432 as a heating element that heats the heating belt 432 from the inner circumferential surface, a holding member 434 that holds the planar heating element 440, and a frame member 452 that supports the holding member 434. In this case, the holding member 434 is supported by the frame member 452 and has a structure that can withstand the pressure from the pressurizing section 414. A unit consisting of a planar heating element 440, a holding member 434, and a frame member 452 is an example of a pressing member.

[0199] In the heating unit 430, both longitudinal ends of the heating belt 432 are supported. For example, circular support members (not shown) are provided respectively, and a heating member gear (not shown) for rotating the heating belt 432 is provided on this support member. One side of this heating member gear is connected to a drive device (not shown) such as a motor inside the image forming apparatus main body. The heating belt 432 is rotated.

[0200] In the heating unit 430, the planar heating element 440 as a heat generating member is formed, for example, as a long plate-like body along the longitudinal direction of the heating unit 430, and has an electrically insulating base material, an insulating layer formed of a polyimide-based heat resistant resin, a pair of electrodes for power supply, and a resistance heating part made of, for example, stainless steel that generates heat when power is supplied from this electrode. Further, the electrode and the resistance heating part are connected by a power supply part, and the electrode, the power supply part, and the resistance heating part are buried in the insulating layer. And the electrode of the planar heating element 440 is grounded with the heating unit side resistor 462 interposed therebetween.

[0201] In the heating unit 430, the holding member 434 is formed of, for example, a resin material such as highly heat resistant LCP (liquid crystal polymer), and a groove part 436 for holding the planar heating element 440 is formed along the longitudinal direction on the side facing the pressing part 414.

[0202] The holding member 434 is pressed by the pressing part 414 while holding the planar heating element 440 in the groove part 436, so as to form a pressing region 470.

[0203] In the heating unit 430, the frame member 452 is formed of, for example, a metal material, supports the holding member 434, and both ends thereof are fixed to support members (not shown) so that the holding member 434 can withstand the pressing from the pressing part 414. Note that a thermistor or the like for temperature detection may be provided in the heating unit 430.

[0204] In the fixing device 410 described above, a pressing region 470 is formed by the roll member 412 of the pressurizing section 414 and the unit consisting of the planar heating element 440, holding member 434 and frame member 452 of the heating section 430, sandwiching the heating belt 432. By passing the recording medium holding the unfixed toner image through this pressing region 470, heat and pressure are applied to fix the unfixed toner image to the recording medium.

[0205] Image forming apparatus Next, the image forming apparatus according to this embodiment will be described. The image forming apparatus according to this embodiment comprises an image holder, a charging device for charging the surface of the image holder, a latent image forming device for forming a latent image on the charged surface of the image holder, a developing device for developing the latent image with toner to form a toner image, a transfer device for transferring the toner image to a recording medium, and a fixing device for fixing the toner image to the recording medium. The fixing device in this embodiment is then applied as the fixing device.

[0206] Here, in the image forming apparatus according to this embodiment, the fixing device may be made into a cartridge that can be attached to and detached from the image forming apparatus. In other words, the image forming apparatus according to this embodiment is The reactor cartridge may include the fixing device described in this embodiment as a component of the cartridge.

[0207] The image forming apparatus according to this embodiment will be described below with reference to the drawings. Figure 5 is a schematic diagram showing an example of an image forming apparatus according to this embodiment.

[0208] As shown in Figure 5, the image forming apparatus 100 according to this embodiment is, for example, an intermediate transfer type image forming apparatus generally called a tandem type, and comprises a plurality of image forming units 1Y, 1M, 1C, and 1K in which toner images of each color component are formed by an electrophotographic method; a primary transfer unit 10 that sequentially transfers (primary transfer) the toner images of each color component formed by each image forming unit 1Y, 1M, 1C, and 1K onto an intermediate transfer belt 15; a secondary transfer unit 20 that transfers (secondary transfer) the superimposed toner images transferred onto the intermediate transfer belt 15 onto a recording medium, paper K; and a fixing device 60 that fixes the secondary transferred image onto the paper K. The image forming apparatus 100 also has a control unit 40 that controls the operation of each device (each part).

[0209] This fixing device 60 is the first embodiment of the fixing device described above. The image forming apparatus 100 may also be configured to include the second embodiment of the fixing device described above.

[0210] Each image forming unit 1Y, 1M, 1C, and 1K of the image forming apparatus 100 is equipped with a photoreceptor 11 that rotates in the direction of arrow A, as an example of an image holder that holds the toner image formed on its surface.

[0211] Around the photoreceptor 11, a charger 12 is provided as an example of a charging means for charging the photoreceptor 11, and a laser exposure unit 13 (indicated by the symbol Bm in the figure) is provided as an example of a latent image forming means for writing an electrostatic latent image onto the photoreceptor 11.

[0212] Furthermore, surrounding the photoreceptor 11, as an example of a developing means, is a developer 14 which contains toners for each color component and visualizes the electrostatic latent image on the photoreceptor 11 using the toner, and a primary transfer roll 16 which transfers the toner images for each color component formed on the photoreceptor 11 to an intermediate transfer belt 15 in a primary transfer unit 10.

[0213] Furthermore, a photoreceptor cleaner 17 is provided around the photoreceptor 11 to remove any residual toner on the photoreceptor 11, and the electrophotographic devices, including the charger 12, laser exposure unit 13, developer unit 14, primary transfer roll 16, and photoreceptor cleaner 17, are sequentially arranged along the rotational direction of the photoreceptor 11. These image forming units 1Y, 1M, 1C, and 1K are arranged in a substantially straight line from the upstream side of the intermediate transfer belt 15 in the order of yellow (Y), magenta (M), cyan (C), and black (K).

[0214] The intermediate transfer belt 15, which is an intermediate transfer material, is a film-like pressure belt with a resin such as polyimide or polyamide as the base layer and containing an appropriate amount of an antistatic agent such as carbon black. Its volume resistivity is 10 6 Ωcm or more 10 14 It is formed to be less than or equal to Ωcm, and its thickness is, for example, about 0.1 mm.

[0215] The intermediate transfer belt 15 is driven (rotated) in a circulating manner in direction B shown in Figure 5 at a speed appropriate for the purpose by various rolls. These various rolls include a drive roll 31 that rotates the intermediate transfer belt 15 by a motor (not shown) with excellent constant-speed performance, a support roll 32 that supports the intermediate transfer belt 15 which extends substantially linearly along the arrangement direction of each photoreceptor 11, a tension-applying roll 33 that applies tension to the intermediate transfer belt 15 and functions as a corrective roll to prevent the intermediate transfer belt 15 from meandering, a back roll 25 provided in the secondary transfer section 20, and a cleaning back roll 34 provided in the cleaning section that scrapes off residual toner on the intermediate transfer belt 15.

[0216] The primary transfer section 10 consists of a primary transfer roll 16 positioned opposite the photoreceptor 11, with an intermediate transfer belt 15 in between. The primary transfer roll 16 consists of a core and a sponge layer, which is an elastic layer fixed around the core. The core is a cylindrical rod made of metal such as iron or stainless steel. The sponge layer is made of a blend of NBR, SBR, and EPDM rubber containing a conductive material such as carbon black, and has a volume resistivity of 10 7.5Ωcm or more 10 8.5 It is a sponge-like cylindrical roll with a diameter of Ωcm or less.

[0217] The primary transfer roll 16 is then pressed against the photoreceptor 11 with the intermediate transfer belt 15 in between, and a voltage (primary transfer bias) with the opposite polarity to the charge polarity of the toner (negative polarity; the same applies hereinafter) is applied to the primary transfer roll 16. As a result, the toner images on each photoreceptor 11 are sequentially electrostatically attracted to the intermediate transfer belt 15, and superimposed toner images are formed on the intermediate transfer belt 15.

[0218] The secondary transfer section 20 comprises a back roll 25 and a secondary transfer roll 22 positioned on the toner image holding surface side of the intermediate transfer belt 15.

[0219] The back roll 25 has a surface made of a blend of EPDM and NBR rubber with dispersed carbon, and the inside is made of EPDM rubber. Its surface resistivity is 10 7 Ω / □ or more 10 10 It is formed to be less than or equal to Ω / □, and its hardness is set to, for example, 70° (Asker C: manufactured by Polymer Instruments, the same applies hereafter). This back roll 25 is positioned on the back side of the intermediate transfer belt 15 and constitutes the opposing electrode of the secondary transfer roll 22, and is in contact with a metal power supply roll 26 to which the secondary transfer bias is stably applied.

[0220] On the other hand, the secondary transfer roll 22 consists of a core and a sponge layer as an elastic layer fixed around the core. The core is a cylindrical rod made of metal such as iron or stainless steel. The sponge layer is made of a blend of NBR, SBR, and EPDM rubber containing conductive materials such as carbon black, and has a volume resistivity of 10 7.5 Ωcm or more 10 8.5 It is a sponge-like cylindrical roll with a diameter of Ωcm or less.

[0221] The secondary transfer roll 22 is then pressed against the back roll 25 with the intermediate transfer belt 15 in between, and the secondary transfer roll 22 is grounded to form a secondary transfer bias between itself and the back roll 25, thereby secondary transferring the toner image onto the paper K that is transported to the secondary transfer section 20.

[0222] Furthermore, an intermediate transfer belt cleaner 35 is provided downstream of the secondary transfer section 20 of the intermediate transfer belt 15, so as to be able to move toward and away from the intermediate transfer belt 15. This cleaner removes residual toner and paper dust from the intermediate transfer belt 15 after secondary transfer and cleans the surface of the intermediate transfer belt 15.

[0223] The intermediate transfer belt 15, the primary transfer section 10 (primary transfer roll 16), and the secondary transfer section 20 (secondary transfer roll 22) are examples of transfer means.

[0224] Meanwhile, upstream of the yellow image forming unit 1Y, a reference sensor (home position sensor) 42 is provided that generates a reference signal, which serves as a reference for determining the image forming timing in each image forming unit 1Y, 1M, 1C, and 1K. This reference sensor 42 recognizes a mark provided on the back side of the intermediate transfer belt 15 and generates a reference signal. Based on the recognition of this reference signal, each image forming unit 1Y, 1M, 1C, and 1K is configured to start image forming according to instructions from the control unit 40. Furthermore, an image density sensor 43 for image quality adjustment is located downstream of the black image forming unit 1K.

[0225] Furthermore, the image forming apparatus according to this embodiment includes, as a means for transporting paper K, a paper storage section 50 for storing paper K, a paper feed roll 51 for taking out and transporting the paper K accumulated in the paper storage section 50 at a predetermined timing, a transport roll 52 for transporting the paper K fed out by the paper feed roll 51, a transport guide 53 for sending the paper K transported by the transport roll 52 to the secondary transfer section 20, a transport belt 55 for transporting the paper K that has been secondarily transferred by the secondary transfer roll 22 to the fixing device 60, and a fixing inlet guide 56 for guiding the paper K to the fixing device 60.

[0226] Next, the basic image formation process of the image forming apparatus according to this embodiment will be described. In the image forming apparatus according to this embodiment, image data output from an image reading device (not shown) or a personal computer (PC) (not shown) is processed by an image processing device (not shown), and then image formation is performed by image forming units 1Y, 1M, 1C, and 1K.

[0227] The image processing device performs various image processing operations on the input image data, including shading correction, positional shift correction, brightness / color space conversion, gamma correction, frame removal, color editing, and movement editing. The processed image data is converted into four-color chromatic data (Y, M, C, K) and output to the laser exposure unit 13.

[0228] In the laser exposure unit 13, according to the input color tone data, an exposure beam Bm emitted from, for example, a semiconductor laser is irradiated onto each of the photoreceptors 11 of the image forming units 1Y, 1M, 1C, and 1K. After the surface of each photoreceptor 11 of the image forming units 1Y, 1M, 1C, and 1K is charged by the charger 12, the surface is scanned and exposed by the laser exposure unit 13, and an electrostatic latent image is formed. The formed electrostatic latent image is then developed as toner images of the respective colors Y, M, C, and K by the respective image forming units 1Y, 1M, 1C, and 1K.

[0229] The toner images formed on the photoreceptors 11 of the image forming units 1Y, 1M, 1C, and 1K are transferred onto the intermediate transfer belt 15 in the primary transfer section 10, where each photoreceptor 11 comes into contact with the intermediate transfer belt 15. More specifically, in the primary transfer section 10, a primary transfer roll 16 applies a voltage (primary transfer bias) with the opposite polarity to the toner's charge polarity (negative polarity) to the substrate of the intermediate transfer belt 15, and the toner images are sequentially superimposed on the surface of the intermediate transfer belt 15 to perform primary transfer.

[0230] After the toner image is sequentially transferred to the surface of the intermediate transfer belt 15, the intermediate transfer belt 15 moves and the toner image is transported to the secondary transfer section 20. When the toner image is transported to the secondary transfer section 20, the transport mechanism rotates the paper feed roll 51 in time with the transport of the toner image to the secondary transfer section 20, and paper K of the desired size is supplied from the paper storage section 50. The paper K supplied by the paper feed roll 51 is transported by the transport roll 52 and reaches the secondary transfer section 20 via the transport guide 53. Before reaching the secondary transfer section 20, the paper K is temporarily stopped, and the position of the paper K and the position of the toner image are aligned by rotating the alignment roll (not shown) in time with the movement of the intermediate transfer belt 15 holding the toner image.

[0231] In the secondary transfer section 20, the secondary transfer roll 22 is pressed against the back roll 25 via the intermediate transfer belt 15. At this time, the paper K, which has been transported in sync with the timing, is sandwiched between the intermediate transfer belt 15 and the secondary transfer roll 22. When a voltage (secondary transfer bias) of the same polarity as the charge polarity (negative polarity) of the toner is applied from the power supply roll 26, a transfer electric field is formed between the secondary transfer roll 22 and the back roll 25. The unfixed toner image held on the intermediate transfer belt 15 is then transferred by the secondary transfer roll 22 and the back roll 25. In the secondary transfer section 20, which is pressurized, the material is electrostatically transferred onto the paper K all at once.

[0232] Subsequently, the paper K on which the toner image has been electrostatically transferred is peeled off the intermediate transfer belt 15 by the secondary transfer roll 22 and transported to the transport belt 55 located downstream of the secondary transfer roll 22 in the paper transport direction. The transport belt 55 transports the paper K to the fuser 60 at an optimal transport speed for the fuser 60. The unfixed toner image on the paper K transported to the fuser 60 is fixed to the paper K by the fuser 60 through a fixing process using heat and pressure. The paper K with the fixed image then transported to the paper discharge and storage section (not shown) located in the discharge section of the image forming apparatus.

[0233] Meanwhile, after the transfer to paper K is complete, any residual toner remaining on the intermediate transfer belt 15 is transported to the cleaning section as the intermediate transfer belt 15 rotates, and is removed from the intermediate transfer belt 15 by the cleaning back roll 34 and the intermediate transfer belt cleaner 35.

[0234] Although this embodiment has been described above, it is not intended to be interpreted as being limited to the above embodiment, and various modifications, changes, and improvements may be made. [Examples]

[0235] The embodiment will be described in more detail below with reference to examples, but this embodiment is not limited to the following examples. In the following description, unless otherwise specified, "parts" and "%" all refer to mass.

[0236] <Preparation of electrostatic image developer> -Preparation of amorphous polyester resin particle dispersion- (Preparation of amorphous polyester resin particle dispersion (1)) Terephthalic acid: 30 moles • Fumaric acid: 70 moles • Bisphenol A ethylene oxide adduct: 5 moles • Bisphenol A propylene oxide adduct: 95 moles The above materials were placed in a 5-liter flask equipped with a stirrer, nitrogen inlet tube, temperature sensor, and rectification column. The temperature was raised to 210°C over 1 hour, and 1 mole of titanium tetraethoxide was added to 100 moles of the above materials. The temperature was raised to 230°C over 0.5 hours while distilling off the generated water, and the dehydration condensation reaction was continued at this temperature for 1 hour, after which the reactants were cooled. In this way, an amorphous polyester resin (1) with a weight-average molecular weight of 18,500, an acid value of 14 mgKOH / g, and a glass transition temperature of 59°C was synthesized.

[0237] In a container equipped with temperature control and nitrogen purging means, 40 parts by mass of ethyl acetate and 25 parts by mass of 2-butanol were added to form a mixed solvent. Then, 100 parts by mass of amorphous polyester resin (1) were gradually added and dissolved. A 10% by mass aqueous ammonia solution (equivalent to 3 times the molar ratio to the acid value of the resin) was added and the mixture was stirred for 30 minutes. Next, the container was purged with dry nitrogen, and the temperature was maintained at 40°C. While stirring the mixture, 400 parts by mass of deionized water was added dropwise at a rate of 2 parts by mass / minute to emulsify it. After the addition was complete, the emulsion was returned to room temperature (20°C to 25°C), and while stirring, it was bubbled with dry nitrogen for 48 hours to reduce the concentrations of ethyl acetate and 2-butanol to 1,000 ppm or less (by mass), obtaining a resin particle dispersion in which resin particles with a volume-average particle size of 200 nm were dispersed. Deionized water was added to the resin particle dispersion to adjust the solid content to 20% by mass to obtain amorphous polyester resin particle dispersion (1).

[0238] -Preparation of a dispersion of crystalline polyester resin particles- (Preparation of crystalline polyester resin particle dispersion (1)) Dodecanedioic acid: 50 moles • 1,6-Hexanediol: 50 moles The above materials were charged into a reaction vessel equipped with a stirrer, nitrogen inlet tube, temperature sensor, and rectification column. The temperature was raised to 160°C over 1 hour, and 0.8 moles of dibutyltin oxide were added per 100 moles of the above materials. The temperature was raised to 180°C over 6 hours while distilling off the generated water, and the reaction was maintained at 180°C for 5 hours with stirring and reflux. Next, the temperature was gradually raised to 230°C under reduced pressure (3 kPa), and the reaction was maintained at 230°C with stirring for 2 hours. The reactants were then cooled. After cooling, solid-liquid separation was performed, and the solid was dried to obtain crystalline polyester resin (1). The weight-average molecular weight of crystalline polyester resin (1) was 29,000.

[0239] Crystalline polyester resin (1): 100 parts by mass Methyl ethyl ketone: 70 parts by mass • Isopropanol: 12 parts by mass • 10% ammonia aqueous solution: 3 parts by mass The above materials were placed in a jacketed reaction vessel equipped with a condenser, thermometer, water dropper, and anchor vane, and the resin was dissolved by stirring at 100 rpm while maintaining the liquid temperature at 80°C in a water-circulating constant temperature bath. Next, the water-circulating constant temperature bath was set to 60°C, and 300 parts by mass of ion-exchanged water, which had been kept at 60°C, was added dropwise at a rate of 3 parts by mass / min to invert the phase and obtain an emulsion. The obtained emulsion was placed in a round-bottom flask and set in an evaporator equipped with a vacuum control unit via a trap bulb. The round-bottom flask was heated in a 60°C water bath while rotating, and after removing the solvent by reducing the pressure to 7 kPa while taking care to prevent bumping, the pressure was returned to atmospheric pressure, and the round-bottom flask was cooled with water to obtain a dispersion. Ion-exchanged water was added to the dispersion to obtain a crystalline polyester resin particle dispersion (1) with a solid content of 20%. The volume-average particle size of the resin particles in the crystalline polyester resin particle dispersion (1) was 160 nm.

[0240] -Preparation of a dispersion of coloring agent particles- (Preparation of a coloring agent particle dispersion (black pigment dispersion)) • Carbon black (Cabot brand, Regal330): 250 units • Anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Neogen SC): 33 parts (60% active ingredient, 8% relative to colorant) • Ion-exchanged water: 750 units In a stainless steel container large enough so that the liquid level would be approximately 1 / 3 of the container's height after adding all the above components, 280 parts of deionized water and 33 parts of anionic surfactant were added. After thoroughly dissolving the surfactant, all of the solid solution pigment was added, and the mixture was stirred using a stirrer until no unwet pigment remained, and thoroughly degassed. After degassing, the remaining deionized water was added, and the mixture was dispersed using a homogenizer (IKA Ultra-Turrax T50) at 5000 rpm for 10 minutes, followed by stirring with a stirrer for 24 hours to degas. After degassing, the mixture was dispersed again using a homogenizer at 6000 rpm for 10 minutes, followed by stirring with a stirrer for 24 hours to degas. Subsequently, the dispersion was dispersed using a high-pressure impact disperser Ultimizer (Sugino Machine Co., Ltd., HJP30006) at a pressure of 240 MPa. The dispersion was performed in approximately 25 passes, calculated based on the total amount of material added and the processing capacity of the equipment. The resulting dispersion was allowed to stand for 72 hours to remove the precipitate, and deionized water was added to adjust the solid content to 15% to obtain a colorant particle dispersion. The volume-average particle size D50 of the particles in this colorant particle dispersion was 135 nm.

[0241] -Preparation of mold release agent dispersion- (Preparation of release agent dispersion) • Synthetic wax (manufactured by Nippon Seiro Co., Ltd., FNP-0090): 50 units • Anionic surfactant (manufactured by Tayca Co., Ltd., TaycaPower): 1 part • Ion-exchanged water: 200 bottles The above materials were mixed and heated to 130°C, dispersed using a homogenizer (IKA Ultra-Turrax T50), and then dispersed again using a Manton-Gorin high-pressure homogenizer (Gorin), to obtain a release agent dispersion (solid content 20% by mass) in which release agent particles were dispersed. The volume-average particle size of the release agent particles was 214 nm.

[0242] -Preparation of Toner 1- • Amorphous polyester resin particle dispersion (1): 553 parts • Crystalline polyester resin particle dispersion (1): 160 parts • Dispersion of coloring agent particles: 117 parts • Release agent dispersion: 100 units • Ion-exchanged water: 500 bottles • Anionic surfactant (Dow Chemical, Dowfax 2A1): 2.9 parts The above components were placed in a 3-liter reaction vessel equipped with a thermometer, pH meter, and stirrer. At a temperature of 25°C, 2.0% nitric acid was added to adjust the pH to 4.5. Then, 123 parts of the prepared 1% aluminum sulfate aqueous solution were added and dispersed for 6 minutes while dispersing at 5,000 rpm using a homogenizer (IKA Japan Co., Ltd.: Ultra-Turrax T50).

[0243] Subsequently, a stirrer and mantle heater were installed in the reaction vessel, and the temperature was increased at a rate of 0.2°C / min up to 40°C, and then at a rate of 0.05°C / min above 40°C, while adjusting the stirrer's rotation speed to ensure the slurry was thoroughly mixed. The particle size was measured every 10 minutes using a multisizer 4e (aperture diameter: 50 μm, manufactured by Coulter). When the volume-average particle size reached 4.2 μm, the temperature was maintained, and 350 parts of amorphous polyester resin particle dispersion (1) were added over 5 minutes. After holding for 30 minutes, the pH was adjusted to 9.0 using a 4% sodium hydroxide aqueous solution. Subsequently, the temperature was increased to 85°C at a rate of 1°C / min while adjusting the pH to 9.0 every 5°C in the same manner, and the temperature was maintained. Particle shape and surface properties were observed using an optical microscope and a scanning electron microscope (FE-SEM), and particle coalescence was confirmed at 5.0 hours, so the container was cooled to 30°C over 5 minutes with cooling water.

[0244] After cooling, the slurry was passed through a 15 μm nylon mesh to remove coarse powder, and the toner slurry that passed through the mesh was filtered under reduced pressure using an aspirator. The toner remaining on the filter paper was finely crushed by hand and added to 10 times the amount of deionized water at 30°C, and stirred for 30 minutes. Subsequently, it was filtered under reduced pressure using an aspirator, the toner remaining on the filter paper was finely crushed by hand and added to 10 times the amount of deionized water at 30°C, stirred for 30 minutes, and then filtered under reduced pressure again using an aspirator, and the electrical conductivity of the filtrate was measured. This operation was repeated until the electrical conductivity of the filtrate was 10 μS / cm or less to wash the toner. The washed toner was finely crushed using a wet-dry granulator (Cormill), and then vacuum-dried in a 35°C oven for 36 hours to obtain toner particles. The volume-average particle size D50v of the obtained toner was 4.70 μm, and the number percentage of toner particles 4 μm or less was 40%.

[0245] Subsequently, 3.3 parts of silica particles were added as an external additive to 100 parts of toner particles. Then, the mixture was mixed for 3 minutes at a peripheral speed of 30 m / s using a Henschel mixer. After that, the mixture was sieved using a vibrating sieve with a mesh size of 45 μm to obtain toner 1.

[0246] -Preparation of Toner 2- Toner 2 was obtained in the same manner as Toner 1, except that the preparation of Toner 1 was changed from "maintaining the temperature when the volume-average particle size reached 4.2 μm" to "maintaining the temperature when the volume-average particle size reached 4.7 μm". The volume-average particle size D50v of the obtained toner was 5.27 μm, and the number percentage of toner particles 4 μm or smaller was 25%.

[0247] -Preparation of Toner 3- Toner 3 was obtained in the same manner as the preparation of Toner 1, except that the procedure for preparing Toner 1 was changed from "maintaining the temperature when the volume-average particle size reached 4.2 μm" to "maintaining the temperature when the volume-average particle size reached 5.0 μm". The volume-average particle size D50v of the obtained toner was 5.56 μm, and the number percentage of toner particles 4 μm or smaller was 15%.

[0248] -Preparing Toner 4- The black toner cartridge NPG-71 for the Canon iRA-C5560III multifunction printer was disassembled, and the toner was extracted and used as toner 4. The volume-average particle size D50v of the toner was 6.80 μm, and the percentage of toner particles 4 μm or smaller was 22%.

[0249] -Prepare toner 5- A black toner cartridge (part number 600477) for a Ricoh IMC6010 multifunction printer was disassembled, and the toner was extracted and used as toner 5. The volume-average particle size D50v of the toner was 5.9 μm, and the percentage of toner particles 4 μm or smaller was 18%.

[0250] -Creating a Career- 500 parts of spherical magnetite particle powder with a volume-average particle size of 0.18 μm were placed in a Henschel mixer and thoroughly mixed. Then, 5 parts of a titanate-based coupling agent were added, and the mixture was heated to 95°C and mixed and stirred for 30 minutes to obtain spherical magnetite particles coated with the titanate-based coupling agent. Next, 6 parts phenol, 10 parts 30% formalin, 500 parts magnetite particles, 7 parts 25% aqueous ammonia, and 400 parts water were placed in a 1 L four-necked flask and mixed and stirred. Then, the temperature was raised to 90°C over 60 minutes while stirring, and the mixture was reacted at the same temperature for 180 minutes. After cooling to 30°C, 500 ml of water was added, the supernatant was removed, and the precipitate was washed with water. This was dried under reduced pressure at 180°C, and coarse powder was removed using a sieve with a mesh size of 106 μm to obtain core material particles with an average particle size of 38 μm. Next, 200 parts of toluene and 35 parts of styrene-methyl methacrylate copolymer (molar ratio of components 10:90, weight-average molecular weight 160,000) were stirred with a stirrer for 90 minutes to obtain a coating resin solution. 1000 parts of core material particles and 70 parts of coating resin solution were placed in a vacuum-degassed kneader coater (rotor-wall clearance 35 mm), stirred at 30 rpm for 30 minutes while maintaining 65°C, then the temperature was raised to 88°C, and the mixture was degassed, dried, and toluene removed under reduced pressure. The mixture was then passed through a 75 μm mesh. The carrier shape factor SF2 was 104.

[0251] -Preparation of the developer- Eight parts of each toner (i.e., any of toners 1 through 5) and 100 parts of carrier were mixed in a V-blender to prepare the developer.

[0252] <Manufacturing of Fixing Belt A1> • SQ1: Organopolysiloxane having a silsesquioxane structure (Type T, manufactured by Konishi Chemical Co., Ltd., "SR-13H", formula: [R 1 SiO 3 / 2 ] m The unit T is expressed as (in the formula, R 1 (Organopolysiloxanes containing only methyl groups): 30% • Dimethylorganopolysiloxane (Type D) (manufactured by Shin-Etsu Chemical Co., Ltd., X34-1053-A / B, the ratio of component A and component B is adjusted to achieve the elastic modulus shown in Table 1): 60% • Heptane: 10% The above components were mixed to obtain a coating for the surface layer.

[0253] A φ168 polyimide substrate was coated with X34-3160-A / B, manufactured by Shin-Etsu Chemical Co., Ltd., as an elastic layer and dried to form an average film thickness of 500 μm. Next, the aforementioned surface layer coating was applied and dried to form a surface layer on the elastic layer with an average film thickness of 25 μm, thereby obtaining a fixing belt A1.

[0254] <Manufacturing of fixing belts A2-A5 and B1-B2> In the production of the fixing belt A1, except that the amounts of SQ1: organopolysiloxane (T-type) having a silsesquioxane structure and dimethylorganopolysiloxane (D-type) used in the surface layer of the fixing belt were changed to the amounts shown in Table 1, and the average film thickness of the surface layer and the average film thickness of the elastic layer were changed to the values in Table 1, fixing belts A2 to A5 and B1 to B2 were obtained in the same manner as the fixing belt A1.

[0255] <Production of Fixing Belt A6> In the production of the fixing belt A1, except that SQ1: organopolysiloxane (T-type) having a silsesquioxane structure used in the surface layer of the fixing belt was changed to the following SQ2, a fixing belt was obtained in the same manner as the fixing belt A1. · SQ2: Organopolysiloxane (T-type, manufactured by KONISHI CHEMICAL CO., LTD., "SR-23", formula: [R 1 SiO 3 / 2 m Organopolysiloxane having only T units (in the formula, R 1 = phenyl group)) represented by

[0256] For the surface layers of the obtained fixing belts A2 to A6 and B1 to B2, "the difference ΔH between the maximum and minimum values of the ultra-micro hardness" and "the tensile elongation rate" were measured. The results are shown in Table 1.

[0257] <Evaluation> In each of the examples and comparative examples, the belts described in Tables 1 and 2 were mounted on a modified machine of the image forming apparatus REVORIA Press PC1120 (manufactured by FUJIFILM BUSINESS INNOVATION CORPORATION), and a developer containing the toner described in Tables 1 and 2 was mounted to prepare an image forming apparatus. The following points were evaluated using this image forming apparatus.

[0258] [Reproducibility of Thin Lines] Characters of "KIBI" were printed on J paper (manufactured by FUJIFILM BUSINESS INNOVATION CORPORATION) at 3 points and 5 points, and it was visually evaluated whether it was legible. -Evaluation Index- ​A: Both 3-point and 5-point markings are clear and easily legible. B: 3-point font is legible despite some blurring; 5-point font is clear and easily legible. C:3 points: Some characters are illegible; 5 points: Some blurring is visible but still legible. At D:3 point, most characters are illegible, and at 5 point, some or all of the characters are illegible.

[0259] [offset] A solid black image was formed on Mirror Coat Platinum 256gsm paper (manufactured by Fujifilm Business Innovation Co., Ltd.), and evaluated by visual observation. The evaluation criteria were as follows: -Evaluation Criteria- A: No offset defects are visible in the image. B: One to two offset defects are visible in the image. C: Three to five offset defects are visible in the image. D: More than six offset defects are visible in the image.

[0260] [Embossing paper adhesion] The black colorants in toners 1-5 were changed to red, green, and blue colorants, and four-color (KRGB) toners were prepared for each of toners 1-5. Using the image forming apparatus in each example, images were printed on A4 paper with 50% image density using four different toners, at a paper feeding speed of 250 mm / s, including the uneven surface of the paper. Afterward, the fixed image was rubbed with a cotton swab, and the degree of fixation was evaluated according to the following criteria. For the A4 paper used, embossed paper with a large surface unevenness (Lezac 66, 151 gsm, manufactured by Tokushu Tokai Paper Co., Ltd.) was used. -Evaluation Criteria- A: The image is fixed to the uneven surface of the paper. B: The image is fixed to the uneven surface of the paper, but when rubbed, one spot shows poor fixation. C: The image is fixed to the uneven surface of the paper, but when rubbed, there are two to four areas where the image is not properly fixed. D: The image is not fixed to the uneven surface of the paper.

[0261] [Table 1]

[0262] The fixing belts of Example 1 and Comparative Examples 1 and 2 (i.e., belts A1, B1, and B2) were used, and the evaluation was conducted using developers (toner 1 to toner 5) with different percentages of toner particles having a particle size of 4 μm or less (referred to as "fine powder amount" in Table 2). The results are shown in Table 2.

[0263] [Table 2]

[0264] The results shown in Tables 1 and 2 indicate that the examples exhibit superior adhesion to embossed paper compared to the comparative examples.

[0265] Preferred embodiments of the present invention are described below. << <1> >> Image holder and, A charging means for charging the surface of the image holder, A means for forming an electrostatic image on the surface of the charged image holder, A developing means comprising: containing an electrostatic image developer containing toner in which the number percentage of toner particles with a particle size of 4 μm or less is 15% or more; and developing the electrostatic image formed on the surface of the image holder as a toner image using the electrostatic image developer; A transfer means for transferring the aforementioned toner image to a recording medium, An organopolysiloxane (T-type) that does not contain a fluorine atom and has a silsesquioxane structure represented by the following formula 1, and a dimethylorganopolysiloxane (D-type), and the content ratio (T-type / D-type) of the organopolysiloxane (T-type) and the dimethylorganopolysiloxane (D-type) is 1 / 9 or more and 9 / 1 or less. A cured product of the composition, and when the ultra-micro hardness is measured at any 50 points by the ultra-micro hardness test defined in JIS Z2255 (2003), the difference ΔH between the maximum value and the minimum value of the ultra-micro hardness is 0% or more and 50% or less. A fixing member having a surface layer, and by bringing the surface layer of the fixing member into contact with the toner image on the recording medium and performing heating and pressurization, a fixing device for fixing the toner image on the recording medium, An image forming apparatus comprising Formula 1 [R 1 SiO 3 / 2 m (In formula 1, R 1 each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aralkyl group, an aryl group, a group represented by -C(=O)-CR 2 3, or a monovalent organic group having a reactive group. A plurality of R 1 may be the same or different from each other. R 2 represents a hydrogen atom, a methyl group, or an ethyl group. When there are a plurality of R 2 , the plurality of R 2 may be the same or different from each other. The monovalent organic group may be substituted with a halogen atom, a hydroxy group, an alkoxy group, an aryloxy group, an aralkyloxy group, or an oxy group. The alkyl group, alkenyl group, alkynyl group, aralkyl group, and aryl group may have a substituent. m represents a positive integer.) <<<2>>> The image forming apparatus according to <<<1>>>, wherein the content ratio (T-type / D-type) in the composition is 3 / 7 or more and 7 / 3 or less. <<<3>>> ​The surface layer has a difference ΔH between the maximum and minimum values ​​of the ultramicrohardness of 0% or more and 40% or less. <1> >> or << <2> The image forming apparatus described in >>. << <4> >> The aforementioned surface layer has a tensile elongation of 50% or more. <1> >>~<< <3> An image forming apparatus as described in any one of the items >>. << <5> >> The aforementioned surface layer has a tensile elongation of 70% or more. <4> >>The image forming apparatus described. << <6> >> The fixing member has an elastic layer and the surface layer on the elastic layer, The average thickness of the surface layer is 30 μm or less, and the average thickness of the elastic layer is 300 μm or more. <1> >>~<< <5> An image forming apparatus as described in any one of the items >>. << <7> >> The average thickness of the surface layer is 10 μm or more and 50 μm or less, and the average thickness of the elastic layer is 150 μm or more and 600 μm or less. <6> The image forming apparatus described in >>. << <8> >> The aforementioned R 1 At least one of them is a methyl group or a phenyl group. <1> >>~<< <7> An image forming apparatus as described in any one of the items >>. << <9> >> The aforementioned R 1 At least one of them is a methyl group. <8> The image forming apparatus described in >>. << <10> >> A charging step in which the surface of the image holder is charged, A step of forming an electrostatic image on the surface of the charged image holder, A developing step in which an electrostatic image developer containing toner having a particle size of 4 μm or less and a number ratio of 15% or more of toner particles is used to develop the electrostatic image formed on the surface of the image holder as a toner image, A transfer step of transferring the toner image formed on the surface of the image holder to the surface of the recording medium, A fixing step in which a toner image is fixed to a recording medium by bringing the surface layer of a fixing member into contact with the toner image on the recording medium and applying heat and pressure, the fixing member having a surface layer having a surface layer having a surface layer where the difference ΔH between the maximum and minimum values ​​of ultramicrohardness measured at 50 arbitrary points according to the ultramicrohardness test specified in JIS Z2255 (2003) is 0% or more and 50% or less, and the surface layer of the fixing member having a surface layer having a surface layer having a surface layer where the difference ΔH between the maximum and minimum values ​​of ultramicrohardness is 0% or more and 50% or less, the surface layer of the fixing member having a surface layer has been brought into contact with the toner image on the recording medium and the toner image is fixed to the recording medium, An image forming method having the following characteristics. Equation 1 [R 1 SiO 3 / 2 ] m (In Equation 1, R 1 Each of these independently represents a hydrogen atom, alkyl group, alkenyl group, alkynyl group, aralkyl group, aryl group, and -C(=O)-CR 2 Represents a group represented by 3, or a monovalent organic group having a reactive group. Multiple R 1 These may be the same or different. R 2 R represents a hydrogen atom, a methyl group, or an ethyl group. 2 If you have multiple R 2 These may be the same or different. The monovalent organic group may be substituted with a halogen atom, a hydroxyl group, an alkoxy group, an aryloxy group, an aralkyloxy group, or an oxy group. The alkyl group, alkenyl group, alkynyl group, aralkyl group, and aryl group may have substituents. m represents a positive integer.

[0266] << <1> >><< <8> >> or << <9> According to the invention described above, compared to an image forming apparatus equipped with a fixing member having a surface layer which is a cured product of a composition with a content ratio (T-type / D-type) of less than 1 / 9 or greater than 9 / 1, or a surface layer in which the difference ΔH between the maximum and minimum values ​​of ultrafine hardness is greater than 50%, an image forming apparatus is provided that exhibits superior fixing of toner images in recesses of a recording medium, even when forming an image with an electrostatic image developer containing toner in which the number ratio of toner particles with a particle size of 4 μm or less is 15% or more on a recording medium having irregularities. << <2> According to the invention described above, compared to an image forming apparatus equipped with a surface layer which is a cured product of a composition having a content ratio (Type T / Type D) of less than 3 / 7 or greater than 7 / 3, an image forming apparatus is provided that exhibits superior fixing of toner images in recesses of a recording medium, even when forming an image with an electrostatic image developer containing toner in which the number ratio of toner particles with a particle size of 4 μm or less is 15% or more on a recording medium having irregularities. << <3> According to the invention described above, compared to an image forming apparatus equipped with a fixing member having a surface layer in which the difference ΔH between the maximum and minimum values ​​of ultra-micro hardness is greater than 40%, an image forming apparatus is provided that exhibits superior fixing of toner images in recesses of a recording medium, even when forming an image with an electrostatic image developer containing toner in which the number ratio of toner particles with a particle size of 4 μm or less is 15% or more on a recording medium having irregularities. << <4> >> or << <5> According to the invention described above, compared to an image forming apparatus equipped with a fixing member having a surface layer with a tensile elongation rate of less than 50%, an image forming apparatus is provided that exhibits superior fixing of toner images in recesses of a recording medium, even when forming an image with an electrostatic image developer containing toner in which the number ratio of toner particles with a particle size of 4 μm or less is 15% or more on a recording medium having an uneven surface. << <6> >> or << <7> According to the invention described above, compared to an image forming apparatus equipped with a fixing member having an average surface layer thickness of more than 30 μm or an elastic layer thickness of less than 300 μm, an image forming apparatus is provided that exhibits superior fixing of toner images in recesses of a recording medium, even when forming an image with an electrostatic image developer containing toner in which the number ratio of toner particles with a particle size of 4 μm or less is 15% or more on a recording medium having irregularities. << <10> According to the invention described above, compared to an image forming method in which the fixing process is performed using a fixing member having a surface layer which is a cured product of a composition with a content ratio (T-type / D-type) of less than 1 / 9 or greater than 9 / 1, or a surface layer in which the difference ΔH between the maximum and minimum values ​​of ultrafine hardness is greater than 50%, an image forming method is provided in which an image is formed using an electrostatic image developer containing toner in which the number ratio of toner particles with a particle size of 4 μm or less is 15% or more on a recording medium having irregularities, and in which an image is formed using an electrostatic image developer. [Explanation of symbols]

[0267] 1Y, 1M, 1C, 1K Image Forming Unit 10 Primary Transfer Section 11 Photoreceptor 12 Chargers 13. Laser exposure unit 14. Developer 15 Intermediate transfer belt 16 Primary transfer roll 17 Photoconductor Cleaner 20 Secondary transfer section 22 Secondary transfer roll 25 Back Roll 26 Power supply roll 31 Drive Roll 32 support rolls 33 Tension-applying roll 34 Cleaning back roll 35 Intermediate Transfer Belt Cleaner 40 Control Unit 42 Reference Sensor 43 Image density sensor 50 Paper storage compartments 51 Paper feed roll 52 Conveyor Rolls 53 Conveyor Guide 55 Conveyor belt 56 Fixing entrance guide 60 Fixing device 61 Heating Roll 62 Compression belt 63 Belt Drive Guide 64 Pressure Pads 64a Front clamping member 64b Peeling and clamping member 65 Retaining member 66 Halogen lamps 68 Sliding member 69 Temperature sensing element 70 Release Member 71. Detachable nails 72 Retaining member 80 Fixing device 82 Sliding member 84. Heated belt 86 Fixing belt module 88 Pressure Roll 89A Halogen Heater 89. Heated pressing roll 90A halogen heater 90 support rolls 92A Halogen Heater 92 Support Roll 94 Posture Correction Roll 96 Support member 98 Support Roll 100 Image forming apparatus 110 Fixing member 110A base material layer 110B Elastic layer 110C surface layer 410 Fixing device 412 Roll Member 414 Pressurized section 416 Shaft 418 Elastic layer 420 Release layer 422 Pressure-side resistor 430 Heating section 432 Heating belt 434 Retaining member 436 Groove 440 Planar heating element 452 Frame members 462 Heating section side resistor 470 Pressing area

Claims

1. Image holder and, A charging means for charging the surface of the image holder, A means for forming an electrostatic image on the surface of the charged image holder, A developing means comprising: containing an electrostatic image developer containing toner in which the number percentage of toner particles with a particle size of 4 μm or less is 15% or more; and developing the electrostatic image formed on the surface of the image holder as a toner image using the electrostatic image developer; A transfer means for transferring the aforementioned toner image to a recording medium, A fixing device comprising a fixing member having a surface layer having a surface layer in which the difference ΔH between the maximum and minimum values ​​of ultramicrohardness measured at 50 arbitrary points according to the ultramicrohardness test specified in JIS Z2255 (2003), is 0% or more and 50% or less, and the surface layer of the fixing member is in contact with the toner image on the recording medium and heating and pressurizing is performed to fix the toner image on the recording medium, and the surface layer of the fixing member is in contact with the toner image on the recording medium. An image forming apparatus comprising: Formula 1 [R] １ SiO ３／２ ] ｍ (In Equation 1, R １ Each of these independently consists of a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aralkyl group, an aryl group, and -C(=O)-CR ２ ３ This represents a group represented by or a monovalent organic group having a reactive group. Multiple R １ These may be the same or different. R ２ represents a hydrogen atom, a methyl group, or an ethyl group. R ２ When having a plurality of R ２ may be the same as or different from each other. The monovalent organic group may be substituted with a halogen atom, a hydroxyl group, an alkoxy group, an aryloxy group, an aralkyloxy group, or an oxy group. The alkyl group, alkenyl group, alkynyl group, aralkyl group, and aryl group may have substituents. (m represents a positive integer.)

2. The image forming apparatus according to claim 1, wherein the content ratio (Type T / Type D) in the composition is 3 / 7 or more and 7 / 3 or less.

3. The image forming apparatus according to claim 1, wherein the surface layer has a difference ΔH between the maximum and minimum values ​​of the ultra-micro hardness of 0% or more and 40% or less.

4. The image forming apparatus according to claim 1, wherein the surface layer has a tensile elongation rate of 50% or more.

5. The image forming apparatus according to claim 4, wherein the surface layer has a tensile elongation rate of 70% or more.

6. The fixing member has an elastic layer and the surface layer on the elastic layer, The image forming apparatus according to claim 1, wherein the average thickness of the surface layer is 30 μm or less, and the average thickness of the elastic layer is 300 μm or more.

7. The image forming apparatus according to claim 6, wherein the average thickness of the surface layer is 10 μm or more and 50 μm or less, and the average thickness of the elastic layer is 150 μm or more and 600 μm or less.

8. The aforementioned R １ The image forming apparatus according to claim 1, wherein at least one of the groups is a methyl group or a phenyl group.

9. The aforementioned R １ The image forming apparatus according to claim 8, wherein at least one of the groups is a methyl group.

10. A charging step in which the surface of the image holder is charged, A step of forming an electrostatic image on the surface of the charged image holder, A developing step in which an electrostatic image developer containing toner having a particle size of 4 μm or less and a number ratio of 15% or more of toner particles is used to develop the electrostatic image formed on the surface of the image holder as a toner image, A transfer step of transferring the toner image formed on the surface of the image holder to the surface of the recording medium, A fixing step in which a toner image is fixed to a recording medium by bringing the surface layer of a fixing member into contact with the toner image on the recording medium and applying heat and pressure, the fixing member having a surface layer having a surface layer having a surface layer where the difference ΔH between the maximum and minimum values ​​of ultramicrohardness measured at 50 arbitrary points according to the ultramicrohardness test specified in JIS Z2255 (2003) is 0% or more and 50% or less, and the toner image is fixed to the recording medium by heating and pressurizing the surface layer of the fixing member, the fixing member having a surface layer having a surface layer having a surface layer where the difference ΔH between the maximum and minimum values ​​of ultramicrohardness measured at 50 arbitrary points according to the ultramicrohardness test specified in JIS Z2255 (2003) is 0% or more and 50% or less, the surface layer of the fixing member, the fixing member having a surface layer having a surface layer having a surface layer having a surface layer where the difference ΔH between the maximum and minimum values ​​of ultramicrohardness is 0% or more and 50% or less, the surface layer of the fixing member, the fixing member having a surface layer, and the heating and pressurizing of the surface layer of the fixing member, the fixing member having a surface layer of an ultramicrohardness measured at 50 arbitrary points according to the ultramicrohardness test specified in JIS Z2255 (2003), the fixing member having a surface layer An image forming method having the following characteristics. Formula 1 [R] １ SiO ３／２ ] ｍ (In Equation 1, R １ Each of these independently consists of a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aralkyl group, an aryl group, and -C(=O)-CR ２ ３ This represents a group represented by or a monovalent organic group having a reactive group. Multiple R １ These may be the same or different. R ２ R represents a hydrogen atom, a methyl group, or an ethyl group. ２ If there are multiple R ２ These may be the same or different. The monovalent organic group may be substituted with a halogen atom, a hydroxyl group, an alkoxy group, an aryloxy group, an aralkyloxy group, or an oxy group. The alkyl group, alkenyl group, alkynyl group, aralkyl group, and aryl group may have substituents. (m represents a positive integer.)

Images