Film, member, transfer device, and image forming apparatus

Abstract

Disclosed are a film, a member, a transfer device, and an image forming apparatus, the film containing a binder resin and an ester-modified silicone resin, and when the static friction coefficient of a first surface of the film is A and the static friction coefficient of a second surface of the film is B, A / B is 0.85 or less.

Description

Technical Field

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

[0002] In an image forming apparatus using an electrophotographic method (a copy machine, a facsimile machine, a printer, etc.), a toner image formed on the surface of an image holding member is transferred and fixed to form an image.

[0003] As a component used in a transfer device of an image forming apparatus, a semiconductive polyimide film containing silicone-modified polyimide is disclosed. Regardless of the laminated structure, the film has a high elastic modulus that reduces the friction coefficient of the outer surface, and the friction coefficient of the inner surface is higher than that of the outer surface (see Japanese Patent Gazette No. 2008-197365). Summary of the Invention

[0004] The present invention aims to provide a film having excellent anti-sticking properties on the first side and excellent anti-slip properties on the second side, compared to a film containing a binder resin and an ester-modified silicone resin, wherein, when the static friction coefficient of the first side of the film is set to A and the static friction coefficient of the second side of the film is set to B, A / B exceeds 0.85.

[0005] According to a first aspect of the present invention, there is provided a film comprising a binder resin and an ester-modified silicone resin, wherein, when the static friction coefficient of the first surface of the film is A and the static friction coefficient of the second surface of the film is B, A / B is 0.85 or less.

[0006] According to a second aspect of the present invention, in the film according to the first aspect, the binder resin is a polyimide-based resin.

[0007] According to the third embodiment of the present invention, in the film involved in the first or second embodiment, after polyester resin particles with a volume average particle size of 4.7 μm are attached to the first surface with a load of 0 N, when air is sprayed onto the first surface from the upper side of the first surface while increasing the injection pressure, the injection pressure is within 16 kPa, and all the polyester resin particles attached to the first surface are separated from the first surface.

[0008] According to a fourth aspect of the present invention, in the film according to any one of the first to third aspects, the content of the ester-modified silicone resin relative to the binder resin is 0.1% by mass or more and 6.0% by mass or less.

[0009] According to a fifth aspect of the present invention, in the film according to any one of the first to fourth aspects, the ester-modified silicone resin has a silanol group at a terminal of at least one of a main chain and a side chain.

[0010] According to a sixth aspect of the present invention, there is provided a member including the film according to any one of the first to fifth aspects.

[0011] According to the seventh embodiment of the present invention, a transfer device is provided, which comprises: an intermediate transfer body, which is composed of the components of the sixth embodiment and has a colorant image transferred on its outer peripheral surface; a primary transfer device, which transfers the colorant image formed on the surface of the image retaining body to the surface of the intermediate transfer body for the first time; and a secondary transfer device, which transfers the colorant image transferred on the surface of the intermediate transfer body to the surface of the recording medium for the second time.

[0012] According to the eighth embodiment of the present invention, there is provided an image forming device comprising: an image retaining member; a charging device for charging the surface of the image retaining member; an electrostatic latent image forming device for forming an electrostatic latent image on the charged surface of the image retaining member; a developing device for storing a developer containing a colorant and developing the electrostatic latent image formed on the surface of the image retaining member by the developer to form a colorant image; the transfer device of the seventh embodiment for transferring the colorant image to the surface of a recording medium; and a fixing device for fixing the colorant image on the surface of the recording medium.

[0013] (Effect)

[0014] According to the first embodiment, a film is provided, which has excellent anti-sticking properties on the first surface and excellent anti-slip properties on the second surface, compared to a film containing a binder resin and an ester-modified silicone resin, when the static friction coefficient of the first surface of the film is set to A and the static friction coefficient of the second surface of the film is set to B, and A / B exceeds 0.85.

[0015] According to the second embodiment, a film is provided, which contains a polyimide resin having excellent mechanical strength, excellent anti-sticking properties on the first side, and excellent anti-slip properties on the second side, compared to a film containing a binder resin and an ester-modified silicone resin, where, when the static friction coefficient of the first side of the film is set to A and the static friction coefficient of the second side of the film is set to B, A / B exceeds 0.85.

[0016] According to the third scheme, a film is provided, which has excellent anti-sticking properties on the first surface and excellent anti-slip properties on the second surface, compared with a case where, after polyester resin particles having a volume average particle size of 4.7 μm are attached to the first surface with a load of 0 N, air is sprayed onto the first surface from the upper side of the first surface while increasing the spray pressure, and the spray pressure exceeds 16 kPa, so that all the polyester resin particles attached to the first surface are separated from the first surface.

[0017] According to the fourth aspect, a film is provided having excellent anti-sticking properties on the first side and excellent anti-slip properties on the second side compared to a film in which the content of the ester-modified silicone resin relative to the binder resin is less than 0.1% by mass or exceeds 6.0% by mass.

[0018] According to the fifth aspect, there is provided a film having excellent release properties on the first surface and excellent anti-slip properties on the second surface, compared to a case where the ester-modified silicone resin is polydimethylsiloxane.

[0019] According to the sixth, seventh and eighth schemes, a component, a transfer device having an intermediate transfer body composed of the component, and an image forming device are provided, wherein the component has excellent anti-sticking properties on the first side and excellent anti-slip properties on the second side, compared with a case where a film containing a binder resin and an ester-modified silicone resin is applied, and when the static friction coefficient of the first side of the film is set to A and the static friction coefficient of the second side of the film is set to B, A / B exceeds 0.85. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic configuration diagram showing an example of the image forming apparatus according to the present embodiment. DETAILED DESCRIPTION

[0021] The following describes embodiments of the present invention. The description and examples are provided to illustrate the embodiments and are not intended to limit the scope of the present invention.

[0022] In this specification, a numerical range expressed using “to” indicates a range including the numerical values ​​described before and after “to” as the minimum value and the maximum value, respectively.

[0023] In the numerical ranges described in the present embodiment, the upper limit or lower limit of one numerical range may be replaced by the upper limit or lower limit of another numerical range described in the present embodiment. In addition, in the numerical ranges described in the present embodiment, the upper limit or lower limit of the numerical range may be replaced by the values ​​shown in the examples.

[0024] In this specification, the term "process" includes not only independent processes but also processes that cannot be clearly distinguished from other processes as long as the intended purpose of the process can be achieved.

[0025] In this specification, when the embodiments are described with reference to the drawings, the structure of the embodiments is not limited to the structure shown in the drawings. In addition, the sizes of the components in each figure are conceptual sizes, and the relative relationship between the sizes of the components is not limited to this.

[0026] In this specification, each component may also include multiple corresponding substances. In the present invention, when referring to the amount of each component in the composition, if there are multiple substances equivalent to each component in the composition, unless otherwise specified, it refers to the total amount of the multiple substances present in the composition.

[0027] In this specification, the “first surface of the film” refers to the surface that becomes the outer peripheral surface of the belt when the film of this embodiment is applied to an intermediate transfer body (intermediate transfer belt composed of an endless film) of a transfer device of an image forming apparatus.

[0028] In this specification, the “second surface of the film” refers to the surface that becomes the inner peripheral surface of the belt when the film of this embodiment is applied to an intermediate transfer body (intermediate transfer belt composed of an endless film) of a transfer device of an image forming apparatus.

[0029] In this specification, "ester-modified silicone resin" includes polyester-modified silicone resin.

[0030] <Film>

[0031] The film of this embodiment contains a binder resin and an ester-modified silicone resin. When the static friction coefficient of the first surface of the film is A and the static friction coefficient of the second surface of the film is B, A / B is 0.85 or less.

[0032] With this structure, compared to a film containing a binder resin and an ester-modified silicone resin, where the static friction coefficient of the first surface of the film is A and the static friction coefficient of the second surface of the film is B, and A / B exceeds 0.85, the first surface has excellent anti-sticking properties and the second surface has excellent anti-slip properties. The reason for this is presumably as follows.

[0033] Conventionally, there is a known technique for adding a release agent to a film in order to impart release properties. However, if a release agent is added to a film, both the first and second surfaces of the film are given release properties, and the anti-slip property is reduced.

[0034] In contrast, in the film of this embodiment, the methyl groups of the ester-modified silicone resin contained in the film-forming coating liquid are easily oriented toward the air-liquid interface during film formation, thereby reducing the static friction coefficient A of the first surface of the film and improving the anti-sticking properties.

[0035] On the other hand, when the film of this embodiment is formed, the silanol groups of the ester-modified silicone resin contained in the film-forming coating liquid are more likely to be oriented at the interface between the coating liquid and the coated surface than at the air-liquid interface due to chemical interactions between the coating liquid and the coated surface. As a result, the static friction coefficient B of the second surface of the film increases, improving its anti-slip properties (this tendency is particularly likely to occur when the coated surface is treated with a silicone resin-based release agent).

[0036] From this, it is presumed that the film of the present embodiment has excellent anti-sticking properties on the first surface and excellent anti-slip properties on the second surface.

[0037] Furthermore, the film of this embodiment exhibits the aforementioned effects. Therefore, when used in an intermediate transfer element (an intermediate transfer belt composed of an endless film) in a transfer device of an image forming apparatus, the outer circumference of the belt exhibits improved toner release. Meanwhile, the inner circumference of the belt is less susceptible to slippage from the belt drive roller. Consequently, transferability to embossed paper is improved, color shift (chromatic aberration) is reduced, and the resulting image quality is enhanced.

[0038] The film of this embodiment will be described in detail below.

[0039] -Binding resin-

[0040] Examples of the binder resin include polyimide resin (PI resin), polyamideimide resin (PAI resin), polyetherketone resin (for example, aromatic polyetheretherketone resin, etc.), polyphenylene sulfide resin (PPS resin), polyetherimide resin (PEI resin), polyester resin, polystyrene resin, polyamide resin, polycarbonate resin, polyethylene terephthalate resin (PET resin), and mixed resins thereof.

[0041] In addition, examples of the binder resin include chloroprene rubber, epichlorohydrin rubber, isoprene rubber, butyl rubber, polyurethane, fluororubber, styrene-butadiene rubber, butadiene rubber, nitrile rubber (NBR), ethylene propylene rubber, ethylene-propylene-diene terpolymer rubber (EPDM), natural rubber, and mixed rubbers thereof.

[0042] Among them, from the viewpoint of improving the mechanical strength of the film, polyimide-based resins such as polyimide (PI) resin and polyamideimide (PAI) resin are preferred.

[0043] As a polyimide resin, the imide compound of the polyamic acid (precursor of a polyimide resin) which is a polymer of tetracarboxylic dianhydride and a diamine compound is mentioned, for example.

[0044] Examples of the polyimide resin include resins having a structural unit represented by the following general formula (I).

[0045]

[0046] In the general formula (I), R 1 represents a tetravalent organic group, R 2 represents a divalent organic group.

[0047] As R 1The tetravalent organic group represented by includes an aromatic group, an aliphatic group, a cycloaliphatic group, a group formed by combining an aromatic group and an aliphatic group, or a group substituted with these groups. Specifically, the tetravalent organic group includes, for example, the residue of tetracarboxylic dianhydride described below.

[0048] As R 2 The divalent organic group represented by includes an aromatic group, an aliphatic group, a cyclic aliphatic group, a group formed by combining an aromatic group and an aliphatic group, or a group substituted with these groups. Specific examples of the divalent organic group include the residue of a diamine compound described below.

[0049] Specific examples of the tetracarboxylic dianhydride used as a raw material for the polyimide resin include pyromellitic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,3,3',4-biphenyltetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,2'-bis(3,4-dicarboxyphenyl)sulfonic acid dianhydride, perylene-3,4,9,10-tetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl)ether dianhydride, and ethylenetetracarboxylic dianhydride.

[0050] Specific examples of the diamine compound used as a raw material for the polyimide resin include 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 3,3'-dichlorobenzidine, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 1,5-diaminonaphthalene, m-phenylenediamine, p-phenylenediamine, 3,3'-dimethyl-4,4'-diphenylenediamine, benzidine, 3,3'-dimethyl Benzidine, 3,3'-dimethoxybenzidine, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl propane, 2,4-bis(amino tert-butyl)toluene, bis(p-β-amino-tert-butylphenyl) ether, bis(p-β-methyl-δ-aminophenyl)benzene, bis-p-(1,1-dimethyl-5-amino-pentyl)benzene, 1-isopropyl-2,4-m-phenylenediamine, m-phenylenediamine, p-phenylenediamine, bis(p-aminocyclohexyl)benzene Methane, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, diaminopropyltetramethylene, 3-methylheptylenediamine, 4,4-dimethylheptylenediamine, 2,11-diaminododecane, 1,2-bis-3-aminopropoxyethane, 2,2-dimethylpropylenediamine, 3-methoxyhexamethylenediamine, 2,5-dimethylheptylenediamine, 3-methylheptylenediamine, 5-methylnonamethylenediamine, 2,17-Diaminoethylhexadecane, 1,4-diaminocyclohexane, 1,10-diamino-1,10-dimethyldecane, 12-diaminooctadecane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, piperazine, H2N(CH2)3O(CH2)2O(CH2)NH2, H2N(CH2)3S(CH2)3NH2, H2N(CH2)3N(CH3)2(CH2)3NH2, etc.

[0051] Examples of the polyamide-imide resin include resins having an imide bond and an amide bond in a repeating unit.

[0052] More specifically, examples of the polyamide-imide resin include polymers of a trivalent carboxylic acid compound (also referred to as tricarboxylic acid) having an acid anhydride group and a diisocyanate compound or a diamine compound.

[0053] As the tricarboxylic acid, for example, trimellitic anhydride and its derivatives are preferred. In addition to the tricarboxylic acid, tetracarboxylic dianhydride, aliphatic dicarboxylic acid, aromatic dicarboxylic acid, etc. may be used in combination.

[0054] Examples of the diisocyanate compound include 3,3'-dimethylbiphenyl-4,4'-diisocyanate, 2,2'-dimethylbiphenyl-4,4'-diisocyanate, biphenyl-4,4'-diisocyanate, biphenyl-3,3'-diisocyanate, biphenyl-3,4'-diisocyanate, 3,3'-diethylbiphenyl-4,4'-diisocyanate, 2,2'-diethylbiphenyl-4,4'-diisocyanate, 3,3'-dimethoxybiphenyl-4,4'-diisocyanate, 2,2'-dimethoxybiphenyl-4,4'-diisocyanate, naphthalene-1,5-diisocyanate, and naphthalene-2,6-diisocyanate.

[0055] Examples of the diamine compound include compounds having the same structure as the above-mentioned isocyanate and having an amino group instead of an isocyanate group.

[0056] The content of the binder resin is preferably 70% to 99.95% by mass, more preferably 75% to 98% by mass, and even more preferably 80% to 90% by mass, relative to 100% by mass of the film.

[0057] -Ester modified silicone resin-

[0058] Examples of ester-modified silicone resins include polyester-modified silicone resins in which at least one of the side chains and terminals of a polysiloxane chain is modified with a polyester. Polyester-modified silicone resins are obtained by reacting an alkoxysilane, an alkoxypolysiloxane, or a mixture thereof with, for example, a polyester resin having two or more hydroxyl groups.

[0059] Furthermore, the ester-modified silicone resin preferably has a silanol group at the end of at least one of the main chain and the side chain. When the ester-modified silicone resin has a silanol group at the end of at least one of the main chain and the side chain, the silanol groups of the ester-modified silicone resin contained in the film-forming coating liquid are easily oriented at the interface between the film-forming coating liquid and the coated surface due to chemical interactions between the film-forming coating liquid and the coated surface, thereby easily improving the anti-slip properties of the second surface of the film.

[0060] The content of the ester-modified silicone resin is preferably 0.1% by mass or more and 6.0% by mass or less relative to 100% by mass of the binder resin, more preferably 1.0% by mass or more and 5.5% by mass or less, and even more preferably 3.0% by mass or more and 5.0% by mass or less. The content of the ester-modified silicone resin is 0.1% by mass or more and 6.0% by mass or less relative to 100% by mass of the binder resin. As a result, the methyl groups of the ester-modified silicone resin contained in the film-forming coating liquid are easily oriented at the gas-liquid interface, and the anti-sticking properties of the first surface of the film are easily improved. Furthermore, the silanol groups of the ester-modified silicone resin contained in the film-forming coating liquid are easily oriented at the interface between the film-forming coating liquid and the coated surface, and the anti-slip properties of the second surface of the film are easily improved.

[0061] The film of this embodiment may contain additives. Examples of the additives include known additives such as conductive agents, reinforcing agents, antioxidants, surfactants, and heat-resistant anti-aging agents, depending on the application of the film.

[0062] Here, a conductive agent will be described as a representative additive.

[0063] Examples of the conductive agent include carbon black, metals (such as aluminum and nickel), metal oxides (such as yttrium oxide and tin oxide), carbon nanotubes, and ion conductive substances (such as potassium titanate and LiCl). Among them, carbon black is preferred.

[0064] These conductive agents may be used alone or in combination of two or more.

[0065] Examples of carbon black include Ketjen black, oil furnace black, channel black (ie, gas black), and acetylene black. Surface-treated carbon black (hereinafter also referred to as "surface-treated carbon black") may also be used as carbon black.

[0066] Surface-treated carbon black is obtained by imparting, for example, carboxyl groups, quinone groups, lactone groups, hydroxyl groups, etc. to its surface. Examples of surface treatment methods include air oxidation in which the carbon black is exposed to air in a high-temperature atmosphere for reaction, a method in which the carbon black is reacted with nitrogen oxides or ozone at room temperature (e.g., 22° C.), and a method in which the carbon black is oxidized with air in a high-temperature atmosphere and then oxidized with ozone at a low temperature.

[0067] The conductive agent may be channel black, and in particular, may be acidic carbon black having a pH of 5.0 or less.

[0068] Examples of acidic carbon black include carbon blacks whose surfaces have been oxidized, for example, carbon blacks whose surfaces have been provided with carboxyl groups, quinone groups, lactone groups, hydroxyl groups, and the like.

[0069] As acidic carbon black, from the viewpoint of improving the transferability to embossed paper, carbon black having a pH of 4.5 or less is preferred, acidic carbon black having a pH of 4.0 or less is more preferred, acidic carbon black having a pH of 3.0 or less is further preferred, acidic carbon black having a pH of 2.0 or more and 3.0 or less is particularly preferred, and acidic carbon black having a pH of 2.0 or more and 2.8 or less is extremely preferred.

[0070] The pH of acidic carbon black is a value measured by the pH measurement method specified in JIS Z8802 (2011).

[0071] When an additive is contained, the content of the additive (eg, conductive agent) is not particularly limited as long as it does not hinder the effects of this embodiment, and may be, for example, 0% by mass or more and 10% by mass or less relative to 100% by mass of the binder resin.

[0072] In the film of this embodiment, when the static friction coefficient of the first surface of the film is set to A and the static friction coefficient of the second surface of the film is set to B, the static friction coefficient A of the first surface of the film is preferably 0.3 to 0.4, and A / B is less than 0.85, preferably less than 0.80, more preferably less than 0.75, and further preferably less than 0.70.

[0073] The static friction coefficient A of the first surface and the static friction coefficient B of the second surface of the film can be measured by using a portable tribometer (Muse TYPE: 94i-II, manufactured by Shinto Scientific Co., Ltd.) under the conditions of temperature 22°C and humidity 55% by mounting each surface of the film on a slider (contact).

[0074] In addition, the membrane of this embodiment is preferably such that after polyester resin particles with a volume average particle size of 4.7 μm are attached to the first surface with a load of 0 N, when air is sprayed onto the first surface from the upper side of the first surface while increasing the spray pressure, the spray pressure is within 16 kPa, and all the polyester resin particles attached to the first surface are separated from the first surface.

[0075] By satisfying the above-mentioned anti-sticking properties, when the film of this embodiment is applied to the intermediate transfer body (intermediate transfer belt) of the transfer device of the image forming device, the non-electrostatic adhesion force generated between the outer peripheral surface of the belt and the colorant is reduced, and even when embossed paper is used as the recording medium, it is easy to suppress the reduction in transferability and the occurrence of white spots in the image.

[0076] Here, whether or not the release property is satisfied is determined as follows.

[0077] First, a 3 cm×4 cm square test piece is collected from the target film.

[0078] Next, polyester resin particles were sprinkled on the surface of the test piece corresponding to the first surface of the film at a temperature of 22°C and a relative humidity of 15% RH, with a voltage of 10 kV applied horizontally to the surface corresponding to the first surface of the film from a height of 15 cm. 2 Adhesion under load (adhesion under load 0N).

[0079] Here, the polyester resin particles are a condensation product of dimethyl fumarate as a dicarboxylic acid and propylene glycol as a diol, and have a weight average molecular weight of 25,000 and a volume average particle size of 4.7 μm.

[0080] Next, air was sprayed from an air nozzle with a diameter of 0.7 mm located 3 cm above the center of the polyester resin particle attachment surface on the test piece at a pressure of 0.1 kPa, and the pressure was increased at 0.5 kPa / sec.

[0081] Then, when the injection pressure reached 16 kPa, if all the polyester resin particles were separated from the test piece, it was judged that the release property was satisfied.

[0082] On the other hand, when polyester resin particles remained on the test piece even when the injection pressure exceeded 16 kPa, it was determined that the release property was unsatisfactory.

[0083] The weight-average molecular weight of the polyester resin particles was measured by gel permeation chromatography (GPC). Molecular weight measurements using GPC were performed using a Tosoh GPC HLC-8120GPC as the measuring instrument, a Tosoh TSKgel SuperHM-M (15 cm) column, and THF as the solvent. The weight-average molecular weight and number-average molecular weight were calculated based on the measurement results using a molecular weight calibration curve prepared with monodisperse polystyrene standard samples.

[0084] The volume average particle size of the polyester resin particles was measured using a Coulter Size Counter II (manufactured by Beckman Coulter), and the electrolyte solution was measured using an ISOTON-II (manufactured by Beckman Coulter).

[0085] During measurement, 0.5 mg to 50 mg of the sample is added to 2 ml of a 5% aqueous solution of a surfactant (preferably sodium alkylbenzenesulfonate) as a dispersant, and this is added to 100 ml to 150 ml of the electrolyte.

[0086] The electrolyte solution containing the sample was dispersed in an ultrasonic disperser for 1 minute, and the particle size distribution of particles with a diameter of 2 μm or more and 60 μm or less was measured using a Coulter particle size analyzer II with an aperture of 100 μm. The number of particles sampled was 50,000.

[0087] For each particle size range (channel) divided according to the measured particle size distribution, the cumulative distribution of volume is plotted from the smaller diameter side, and the particle diameter at which the cumulative distribution reaches 50% is defined as the volume average particle diameter D50v.

[0088] The film of the present embodiment can be produced by, for example, applying a coating liquid for forming a film (film-forming coating liquid) on a substrate and drying the coating liquid.

[0089] <Components>

[0090] The component of this embodiment includes the film of this embodiment. The component of this embodiment may also include the above-mentioned film as a layer constituting the outer peripheral surface. The component of this embodiment may be any of a single-layer component of the film of this embodiment described above, and a component in which the film of this embodiment described above is provided on a substrate.

[0091] When the component of this embodiment is used in an intermediate transfer member for an electrophotographic image forming apparatus, the component may be a single layer of the film of this embodiment described above, or a laminate having the film as the outermost layer. In the laminate, layers other than the film described above (e.g., a substrate layer provided with the film, an elastic layer provided between the film and the substrate layer, etc.) may be known layers provided on the intermediate transfer member.

[0092] <Transfer device>

[0093] Next, the transfer device of this embodiment will be described.

[0094] The transfer device of this embodiment includes:

[0095] an intermediate transfer member composed of the components of the present embodiment described above, having a toner image transferred to its outer peripheral surface;

[0096] a primary transfer device that primarily transfers the toner image formed on the surface of the image holding member to the surface of the intermediate transfer member; and

[0097] The secondary transfer device secondarily transfers the toner image transferred to the surface of the intermediate transfer body to the surface of the recording medium.

[0098] (Primary transfer device)

[0099] In the primary transfer device, a primary transfer member is disposed opposite to an image holder with an intermediate transfer member interposed therebetween. In the primary transfer device, a voltage having a polarity opposite to the toner charge polarity is applied to the intermediate transfer member by the primary transfer member, thereby primary transferring the toner image to the outer peripheral surface of the intermediate transfer member.

[0100] (Secondary transfer device)

[0101] In the secondary transfer device, a secondary transfer member is positioned on the toner image holding side of the intermediate transfer member. Furthermore, the secondary transfer device includes, for example, a secondary transfer member and a back member positioned on the side of the intermediate transfer member opposite to the toner image holding side. In the secondary transfer device, a transfer electric field is generated by sandwiching the intermediate transfer member and the recording medium between the secondary transfer member and the back member, thereby performing a secondary transfer of the toner image on the intermediate transfer member onto the recording medium.

[0102] The secondary transfer member may be a secondary transfer roller or a secondary transfer belt. In addition, the back member may be, for example, a back roller.

[0103] Furthermore, the transfer device of this embodiment may also be a transfer device that transfers a toner image onto the surface of a recording medium via multiple intermediate transfer bodies. Specifically, the transfer device may be a transfer device that, for example, primarily transfers a toner image from an image holder to a first intermediate transfer body, then secondarily transfers the toner image from the first intermediate transfer body to a second intermediate transfer body, and then tertiarily transfers the toner image from the second intermediate transfer body to the recording medium.

[0104] In the transfer device, the intermediate transfer body formed of the film of the present embodiment described above is applied to at least one of the plurality of intermediate transfer bodies.

[0105] Image forming device

[0106] The image forming apparatus according to this embodiment will be described.

[0107] The image forming apparatus of this embodiment includes:

[0108] An image retaining member; a charging device that charges the surface of the image retaining member; an electrostatic latent image forming device that forms an electrostatic latent image on the surface of the charged image retaining member; a developing device that contains a developer containing a colorant and develops the electrostatic latent image formed on the surface of the image retaining member to form a colorant image with the developer; a transferring device that transfers the colorant image to the surface of a recording medium; and a fixing device that fixes the colorant image to the surface of the recording medium.

[0109] Furthermore, as the transfer device, the transfer device of this embodiment is applied.

[0110] Here, in the image forming apparatus of this embodiment, the transfer device and the fixing device can be detachably mounted on the image forming apparatus. That is, the image forming apparatus of this embodiment can also include the transfer device of this embodiment as a component of the process cartridge.

[0111] Hereinafter, the image forming apparatus according to the present embodiment will be described with reference to the drawings.

[0112] Figure 1This is a schematic structural diagram showing the structure of the image forming apparatus according to this embodiment.

[0113] like Figure 1 As shown, the image forming apparatus 100 of this embodiment is, for example, an image forming apparatus of the intermediate transfer method generally known as a tandem type, and includes: a plurality of image forming units 1Y, 1M, 1C, and 1K, which form toner images of respective color components by electrophotography; a primary transfer section 10, which sequentially transfers (primarily transfers) the toner images of respective color components formed by the image forming units 1Y, 1M, 1C, and 1K onto an intermediate transfer belt 15; a secondary transfer section 20, which transfers (secondarily transfers) the superimposed toner images transferred onto the intermediate transfer belt 15 onto a recording medium, i.e., paper K; and a fixing device 60, which fixes the secondary transferred images onto the paper K. The image forming apparatus 100 also includes a control section 40 for controlling the operation of each device (unit).

[0114] Each of the image forming units 1Y, 1M, 1C, and 1K of the image forming apparatus 100 includes a photoreceptor 11 that rotates in the direction of arrow A as an example of an image holding member that holds a toner image formed on a surface.

[0115] Around the photoconductor 11, a charger 12 for charging the photoconductor 11 is provided as an example of a charging device, and a laser exposer 13 (the exposure beam is represented by the symbol Bm in the figure) for writing an electrostatic latent image on the photoconductor 11 is provided as an example of an electrostatic latent image forming device.

[0116] In addition, around the photosensitive body 11, as an example of a developing device, there is provided a developer 14 that contains colorant of each color component and visualizes the electrostatic latent image on the photosensitive body 11 through the colorant, and a primary transfer roller 16 that transfers the colorant image of each color component formed on the photosensitive body 11 to the intermediate transfer belt 15 through the primary transfer section 10.

[0117] Furthermore, a photoreceptor cleaner 17 is provided around the photoreceptor 11 to remove residual toner from the photoreceptor 11. The electrophotographic devices, including the charger 12, laser exposure unit 13, developer 14, primary transfer roller 16, and photoreceptor cleaner 17, are arranged in this order along the rotational direction of the photoreceptor 11. These image forming units 1Y, 1M, 1C, and 1K are arranged in a generally 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).

[0118] The intermediate transfer belt 15 as the intermediate transfer body is composed of a film-shaped pressure belt with a resin as the base layer and an appropriate amount of antistatic agent such as carbon black. 6 Ωcm or more and 10 14The thickness is Ωcm or less, and is, for example, about 0.1mm.

[0119] The intermediate transfer belt 15 passes through various rollers. Figure 1 The intermediate transfer belt 15 is cyclically driven (rotated) at a target speed in the direction B shown. The various rollers include: a drive roller 31, which is driven by a motor (not shown) with excellent speed control to rotate the intermediate transfer belt 15; a support roller 32, which supports the intermediate transfer belt 15, which extends substantially linearly along the arrangement direction of the photoreceptors 11; a tensioning roller 33, which applies tension to the intermediate transfer belt 15 and functions as a correction roller to prevent the intermediate transfer belt 15 from meandering; a back roller 25, which is provided in the secondary transfer section 20; and a cleaning back roller 34, which is provided in the cleaning section to scrape off residual toner on the intermediate transfer belt 15.

[0120] The primary transfer unit 10 is composed of a primary transfer roller 16 disposed opposite the photoreceptor 11 via an intermediate transfer belt 15. The primary transfer roller 16 is composed of a core and a sponge layer as an elastic layer fixed around the core. The core is a cylindrical rod made of a metal such as iron or SUS. The sponge layer is made of a rubber blend of NBR, SBR, and EPDM with a conductive agent such as carbon black, and has a volume resistivity of 10 7.5 Ωcm or more and 10 8.5 A sponge-like cylindrical roller with a thickness of Ωcm or less.

[0121] The primary transfer roller 16 is placed in pressure contact with the photoreceptor 11 across the intermediate transfer belt 15. Furthermore, a voltage (primary transfer bias) with a polarity opposite to the toner charge polarity (negative polarity, the same applies hereinafter) is applied to the primary transfer roller 16. As a result, the toner images on each photoreceptor 11 are sequentially electrostatically attracted to the intermediate transfer belt 15, forming overlapping toner images on the intermediate transfer belt 15.

[0122] The secondary transfer section 20 includes a back roller 25 and a secondary transfer roller 22 disposed on the toner image holding surface side of the intermediate transfer belt 15 .

[0123] The back roller 25 is a tube made of a mixed rubber of EPDM and NBR with carbon dispersed on the surface, and the inside is made of EPDM rubber. 7 Ω / □ or more and 10 10 The back roller 25 is arranged on the back side of the intermediate transfer belt 15 and constitutes the counter electrode of the secondary transfer roller 22. It is arranged in contact with a metal power supply roller 26 to which a secondary transfer bias voltage is stably applied.

[0124] On the other hand, the secondary transfer roller 22 is composed 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 SUS. The sponge layer is made of a rubber mixture of NBR, SBR, and EPDM mixed with a conductive agent such as carbon black, and has a volume resistivity of 10 7.5 Ωcm or more and 10 8.5 A sponge-like cylindrical roller with a thickness of Ωcm or less.

[0125] The secondary transfer roller 22 is pressed against the back roller 25 via the intermediate transfer belt 15 . The secondary transfer roller 22 is grounded, and a secondary transfer bias is generated between the secondary transfer roller 22 and the back roller 25 , so as to transfer the toner image onto the paper K conveyed to the secondary transfer section 20 .

[0126] In addition, on the downstream side of the secondary transfer section 20 of the intermediate transfer belt 15, an intermediate transfer belt cleaner 35 that removes residual colorant and paper powder on the intermediate transfer belt 15 after secondary transfer and cleans the surface of the intermediate transfer belt 15 is set to be able to freely approach or move away from the intermediate transfer belt 15.

[0127] The intermediate transfer belt 15 , the primary transfer section 10 (primary transfer roller 16 ), and the secondary transfer section 20 (secondary transfer roller 22 ) correspond to an example of a transfer device.

[0128] On the other hand, a reference sensor (home position sensor) 42 is provided upstream of the yellow image forming unit 1Y. This reference sensor 42 generates a reference signal that serves as a reference for determining the image formation timing in each of the image forming units 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 and an instruction from the control unit 40, each of the image forming units 1Y, 1M, 1C, and 1K starts image formation.

[0129] Furthermore, an image density sensor 43 for image quality adjustment is provided on the downstream side of the black image forming unit 1K.

[0130] Furthermore, in the image forming apparatus of the present embodiment, as a conveying device for conveying paper K, there is provided a paper receiving section 50 for receiving paper K, a paper feed roller 51 for taking out and conveying paper K accumulated in the paper receiving section 50 at a predetermined timing, a conveying roller 52 for conveying paper K successively discharged by the paper feed roller 51, a conveying guide 53 for conveying paper K conveyed by the conveying roller 52 to the secondary transfer section 20; a conveying belt 55 for conveying paper K conveyed after secondary transfer by the secondary transfer roller 22 to the fixing device 60, and a fixing entrance guide 56 for guiding paper K to the fixing device 60.

[0131] Next, a basic image generation process of the image forming apparatus according to this embodiment will be described.

[0132] In the image forming apparatus of this embodiment, image data output from an image reading device (not shown) or a personal computer (PC) (not shown) is processed by an image processing device (not shown), and then image forming units 1Y, 1M, 1C, and 1K execute image generation operations.

[0133] The image processing device performs image processing on the input reflectance data, including shading correction, positional offset correction, brightness / color space conversion, gamma correction, frame removal, color editing, motion editing, and other image editing techniques. The processed image data is converted into grayscale data for the four colors Y, M, C, and K, and then output to the laser exposure device 13.

[0134] In the laser exposure device 13, based on input colorant grayscale data, exposure light beams Bm emitted from, for example, a semiconductor laser are directed toward the photoreceptors 11 of the image forming units 1Y, 1M, 1C, and 1K. After the surfaces of the photoreceptors 11 of the image forming units 1Y, 1M, 1C, and 1K are charged by the charger 12, the laser exposure device 13 scans and exposes the surfaces, forming electrostatic latent images. The formed electrostatic latent images are developed into toner images of the respective colors Y, M, C, and K by the image forming units 1Y, 1M, 1C, and 1K.

[0135] 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 is in contact with the intermediate transfer belt 15. More specifically, in the primary transfer section 10, a voltage (primary transfer bias) having a polarity opposite to the toner charge polarity (negative polarity) is applied to the substrate of the intermediate transfer belt 15 by the primary transfer roller 16. This causes the toner images to be sequentially superimposed on the surface of the intermediate transfer belt 15, thereby performing the primary transfer.

[0136] After the toner images are sequentially transferred primarily onto the surface of the intermediate transfer belt 15, the intermediate transfer belt 15 moves, and the toner images are transported to the secondary transfer section 20. As the toner images are transported to the secondary transfer section 20, the paper feed roller 51 in the transport device rotates in sync with the timing of the toner image's transport to the secondary transfer section 20, and paper K of a target size is supplied from the paper storage section 50. The paper K supplied by the paper feed roller 51 is transported by the transport roller 52 and, via the transport guide 53, reaches the secondary transfer section 20. Before reaching the secondary transfer section 20, the paper K temporarily stops, and the registration roller (not shown) rotates in sync with the movement of the intermediate transfer belt 15 holding the toner images, thereby completing the alignment between the position of the paper K and the position of the toner images.

[0137] In the secondary transfer section 20, the secondary transfer roller 22 is pressed against the back roller 25 via the intermediate transfer belt 15. At this point, the paper K, which is being transported in a timely manner, is sandwiched between the intermediate transfer belt 15 and the secondary transfer roller 22. At this point, when a voltage (secondary transfer bias) having the same polarity as the toner charge polarity (negative polarity) is applied from the power supply roller 26, a transfer electric field is formed between the secondary transfer roller 22 and the back roller 25. The unfixed toner image held on the intermediate transfer belt 15 is electrostatically transferred onto the paper K in a single pass in the secondary transfer section 20, which is pressurized by the secondary transfer roller 22 and the back roller 25.

[0138] The paper K onto which the toner image has been electrostatically transferred is then conveyed, while still being peeled from the intermediate transfer belt 15 by the secondary transfer roller 22, to a conveyor belt 55 located downstream of the secondary transfer roller 22 in the paper conveying direction. The conveyor belt 55 conveys the paper K to the fixing device 60 at an optimal conveying speed consistent with that in the fixing device 60. The unfixed toner image on the paper K conveyed to the fixing device 60 is fixed to the paper K by the fixing device 60 through a fixing process under heat and pressure. The paper K with the fixed image formed thereon is then conveyed to a paper discharge storage unit (not shown) provided in the discharge section of the image forming apparatus.

[0139] On the other hand, after the transfer to the paper K is completed, the residual toner remaining on the intermediate transfer belt 15 is conveyed to the cleaning section as the intermediate transfer belt 15 rotates, and is removed from the intermediate transfer belt 15 by the cleaning back roller 34 and the intermediate transfer belt cleaner 35 .

[0140] As mentioned above, although this embodiment was demonstrated, it is not interpreted as being limited to the said embodiment, Various deformation|transformation, change, and improvement are possible.

[0141] [Example]

[0142] Hereinafter, the present embodiment will be described in further detail with reference to examples, but the present embodiment is not limited to the following examples.

[0143] <Example 1>

[0144] To a polyimide varnish (JIV-300R, manufactured by JFE Chemical Co., Ltd., solid content 18% by mass), an ester-modified silicone resin (KR-5235, manufactured by Shin-Etsu Chemical Co., Ltd.) was added in an amount of 5.0% by mass relative to the imidized polyimide resin, and carbon black (FW200, manufactured by Orion Engineering Carbon Co., Ltd.) was added in an amount of 20% by mass relative to the imidized polyimide resin. The mixture was stirred and mixed for 60 minutes using a centrifugal mixer (manufactured by Keyence Corporation) to obtain a coating liquid for film formation.

[0145] Next, the film-forming coating liquid was applied to the cylindrical substrate by spiral coating to a film thickness of 100 μm, and then heat-dried at 160° C. for 30 minutes and at 300° C. for 1 hour to obtain a ring-shaped film.

[0146] Here, a release agent (SEPA-COAT, manufactured by Shin-Etsu Chemical Co., Ltd.) was applied to the outer peripheral surface of the cylindrical substrate.

[0147] <Example 2>

[0148] A ring-shaped film was obtained in the same manner as in Example 1 except that the amount of the ester-modified silicone resin added was 0.30% by mass relative to the imidized polyimide resin.

[0149] <Example 3>

[0150] A ring-shaped film was obtained in the same manner as in Example 1 except that the polyimide varnish was changed to a polyamide-imide varnish (HPC-9000F-8H, manufactured by Resonac Corporation) and the amount of the ester-modified silicone resin added was changed to 3.0% by mass relative to the imidized polyamide-imide resin.

[0151] Comparative Example 1

[0152] A ring-shaped film was obtained in the same manner as in Example 1 except that the ester-modified silicone resin was changed to 3.0% by mass of dimethylpolysiloxane (PDMS) (KF-96A-5, manufactured by Shin-Etsu Chemical Co., Ltd.).

[0153] Comparative Example 2

[0154] A ring-shaped film was obtained in the same manner as in Example 1 except that the ester-modified silicone resin was changed to 5.0% by mass of dimethylpolysiloxane (PDMS) (KF-96A-5, manufactured by Shin-Etsu Chemical Co., Ltd.).

[0155] Comparative Example 3

[0156] A ring-shaped film was obtained in the same manner as in Example 1 except that the amount of the ester-modified silicone resin added was 0.05% by mass relative to the imidized polyimide resin.

[0157] Comparative Example 4

[0158] A ring-shaped film was obtained in the same manner as in Example 1 except that the amount of the ester-modified silicone resin added was 7.0% by mass relative to the polyimide resin after imidization.

[0159] <Comparative Example 5>

[0160] A ring-shaped film was obtained in the same manner as in Example 1 except that a release agent (GW-4500, manufactured by Daikin Industries, Ltd.) was applied to the outer peripheral surface of the cylindrical substrate.

[0161] Furthermore, the ester-modified silicone resin (KR-5235, manufactured by Shin-Etsu Chemical Co., Ltd.) is an ester-modified silicone resin having a silanol group at the terminal of at least one of the main chain and the side chain.

[0162] <Measurement and Evaluation>

[0163] -Static friction coefficient-

[0164] For the annular films obtained in the Examples and Comparative Examples, the static friction coefficients of the first surface (i.e., the outer surface) and the second surface (i.e., the inner surface) were measured according to the above method. Furthermore, the ratio of the static friction coefficients of the first and second surfaces was calculated. The results are shown in Table 1.

[0165] - Anti-stick properties -

[0166] The annular films obtained in Examples and Comparative Examples were measured by the above-mentioned method for the air jet pressure when all polyester resin particles (volume average particle size 4.7 μm) adhering to the first surface of the film were separated from the first surface.

[0167] -Transferability-

[0168] The endless films obtained in the Examples and Comparative Examples were used as intermediate transfer belts in a modified "DocuColor-7171P" printer manufactured by Fujifilm Business Innovations. Under conditions of 22°C and 55% relative humidity, the recording medium was conveyed at a speed of 366 mm / s in the secondary transfer area. A blue solid image was formed on embossed paper (LEATHAC66, 204 gsm) and the transferability of the embossed paper was evaluated by visual inspection for whitening in the concave areas. The evaluation was conducted according to the following criteria. The results are shown in Table 1. A toner with a volume average particle size of 4.7 μm was used.

[0169] A: No whitening occurs

[0170] B: produces a slight color change

[0171] C: Produces a clear color change

[0172] D: produces white spots

[0173] In addition, under the same conditions, a comprehensive chart was output and color shift (color shift) was visually evaluated. The evaluation was performed according to the following criteria. The results are shown in Table 1.

[0174] A: No color shift

[0175] B: There is color shift, but within the reference value

[0176] C: Produces color deviation exceeding the reference value

[0177] [Table 1]

[0178]

[0179] As shown in Table 1, it can be seen that the film of this embodiment has a low ejection pressure, good transferability, and excellent release properties on the first surface.

[0180] Furthermore, it was found that the film of this example had little color shift and excellent anti-slip properties on the second surface.

[0181] (Note) (((1)))

[0183] A film comprising:

[0184] a bonding resin; and

[0185] Ester modified silicone resin,

[0186] When the static friction coefficient of the first surface of the film is represented by A and the static friction coefficient of the second surface of the film is represented by B, A / B is 0.85 or less. (((2)))

[0188] The film according to (((1))), wherein

[0189] The bonding resin is a polyimide resin. (((3)))

[0191] The film according to (((1))) or (((2))), wherein

[0192] After polyester resin particles with a volume average particle size of 4.7 μm are attached to the first surface with a load of 0 N, when air is sprayed onto the first surface from the upper side of the first surface while increasing the injection pressure, the injection pressure is within 16 kPa, and all the polyester resin particles attached to the first surface are separated from the first surface. (((4)))

[0194] The film according to any one of (((1))) to (((3))), wherein

[0195] The content of the ester-modified silicone resin relative to the binder resin is 0.1% by mass or more and 6.0% by mass or less. (((5)))

[0197] The film according to any one of (((1))) to (((4))), wherein

[0198] The ester-modified silicone resin has a silanol group at the terminal of at least one of a main chain and a side chain. (((6)))

[0200] A component comprising the film according to any one of (((1))) to (((5))). (((7)))

[0202] A transfer device, comprising:

[0203] an intermediate transfer member, the intermediate transfer member being composed of the member described in (((6))) and having a toner image transferred to its outer peripheral surface;

[0204] a primary transfer device for primarily transferring a toner image formed on a surface of an image holding member to a surface of the intermediate transfer member; and

[0205] A secondary transfer device secondarily transfers the toner image transferred to the surface of the intermediate transfer body to a surface of a recording medium. (((8)))

[0207] An image forming apparatus comprising:

[0208] Image holding body;

[0209] a charging device for charging the surface of the image holding member;

[0210] an electrostatic latent image forming device for forming an electrostatic latent image on the charged surface of the image holding member;

[0211] a developing device containing a developer containing a toner, and developing the electrostatic latent image formed on the surface of the image holding member with the developer to form a toner image;

[0212] (((7))) The transfer device transfers the toner image to a surface of a recording medium; and

[0213] A fixing device fixes the toner image on a surface of a recording medium.

[0214] According to (((1))), a film is provided, which has excellent anti-sticking properties on the first side and excellent anti-slip properties on the second side, compared with a film containing a binder resin and an ester-modified silicone resin, when the static friction coefficient of the first side of the film is set to A and the static friction coefficient of the second side of the film is set to B, and A / B exceeds 0.85.

[0215] According to (((2))), a film is provided, which contains a polyimide resin having excellent mechanical strength, excellent anti-sticking properties on the first side, and excellent anti-slip properties on the second side, compared with a film containing a binder resin and an ester-modified silicone resin, when the static friction coefficient of the first side of the film is set to A and the static friction coefficient of the second side of the film is set to B, and A / B exceeds 0.85.

[0216] According to (((3))), a film is provided, which has excellent anti-sticking properties on the first surface and excellent anti-slip properties on the second surface, compared with a case where, after polyester resin particles having a volume average particle size of 4.7 μm are attached to the first surface with a load of 0 N, air is sprayed onto the first surface from the upper side of the first surface while increasing the spray pressure, and the spray pressure exceeds 16 kPa, and all the polyester resin particles attached to the first surface are separated from the first surface.

[0217] According to (((4))), a film is provided, which has excellent anti-sticking properties on the first side and excellent anti-slip properties on the second side, compared with the case where the content of the ester-modified silicone resin relative to the binder resin is less than 0.1% by mass or exceeds 6.0% by mass.

[0218] According to (((5))), there is provided a film having excellent anti-sticking properties on the first side and excellent anti-slip properties on the second side, compared to a case where the ester-modified silicone resin is polydimethylsiloxane.

[0219] According to (((6))), (((7))) and (((8))), a component, a transfer device having an intermediate transfer body composed of the component and an image forming device are provided, wherein the component has excellent anti-sticking properties on the first side and excellent anti-slip properties on the second side, compared with a film containing a binder resin and an ester-modified silicone resin, wherein when the static friction coefficient of the first side of the film is set to A and the static friction coefficient of the second side of the film is set to B, A / B exceeds 0.85.

Claims

1. A film, characterized in that contain: a bonding resin; and Ester modified silicone resin, When the static friction coefficient of the first surface of the film is represented by A and the static friction coefficient of the second surface of the film is represented by B, A / B is 0.85 or less.

2. The film according to claim 1, wherein The bonding resin is a polyimide resin.

3. The film according to claim 1 or 2, wherein After polyester resin particles with a volume average particle size of 4.7 μm are attached to the first surface with a load of 0 N, when air is sprayed onto the first surface from the upper side of the first surface while increasing the injection pressure, the injection pressure is within 16 kPa, and all the polyester resin particles attached to the first surface are separated from the first surface.

4. The film according to any one of claims 1 to 3, wherein The content of the ester-modified silicone resin relative to the binder resin is 0.1% by mass or more and 6.0% by mass or less.

5. The film according to any one of claims 1 to 4, wherein The ester-modified silicone resin has a silanol group at the terminal of at least one of a main chain and a side chain.

6. A component, characterized in that A film according to any one of claims 1 to 5.

7. A transfer device, characterized in that: have: an intermediate transfer member, the intermediate transfer member being composed of the member according to claim 6 and having a toner image transferred to its outer peripheral surface; a primary transfer device for primarily transferring a toner image formed on a surface of an image holding member to a surface of the intermediate transfer member; and A secondary transfer device secondarily transfers the toner image transferred to the surface of the intermediate transfer body to a surface of a recording medium.

8. An image forming apparatus, characterized in that: have: Image holding body; a charging device for charging the surface of the image holding member; an electrostatic latent image forming device for forming an electrostatic latent image on the charged surface of the image holding member; a developing device containing a developer containing a toner, and developing the electrostatic latent image formed on the surface of the image holding member with the developer to form a toner image; The transfer device according to claim 7, wherein the transfer device transfers the toner image to a surface of a recording medium; and A fixing device fixes the toner image on a surface of a recording medium.

Images