JP2009151291A - Image forming method and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming method and an image forming apparatus capable of producing favorable electrophotographic images while preventing comet-like image defects (so called as dash marks) in an image forming method using an intermediate transfer member (also called as an intermediate transfer belt when a belt type intermediate transfer member is used) in an electrophotographic process. <P>SOLUTION: The image forming method includes a step of transferring a toner image formed on an electrophotographic photoreceptor onto an intermediate transfer member. The method is characterized in that a dispersion force component (γ<SB>S</SB><SP>d</SP>) of the free energy on the transfer member surface is ≤40 mN/m and the surface layer of the electrophotographic photoreceptor contains a structural component prepared by reacting and curing a curable compound. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electrophotographic image forming method and an image forming apparatus using an intermediate transfer member.

  In addition to copiers and printers for office use, electrophotographic image forming apparatuses have recently become widespread in the printing field called light printing, and can print thousands of pages in a short time without printing. It has come to attract attention from the merit.

  In one of the electrophotographic image forming methods, a toner image formed on a photoreceptor is transferred onto a transfer intermediate, and image formation is performed through a process of performing secondary transfer onto the recording medium from the transfer intermediate. There is something. One embodiment of the intermediate transfer member is an intermediate transfer belt using an endless belt made of resin, and the improvement of the intermediate transfer belt has been promoted so far in order to develop good transfer performance. .

  For example, by using a material that imparts high water repellency and that exhibits a triboelectric charge property of reverse polarity to that of the toner on the surface of the intermediate transfer belt, it is stable without the occurrence of local transfer defects called worm-eating prints. There is a technique that enables transfer (see, for example, Patent Document 1). Further, a technique has been disclosed in which a layer containing a conductive filler and a surface layer containing a silicone resin are provided so that the toner releasability can be maintained over a long period of time and the tensile strength can be improved (for example, Patent Document 2).

  Recently, a technique for improving the performance of the surface area of the intermediate transfer belt has been studied so that a high-definition toner image can be accurately transferred in accordance with the progress of digitization. Specifically, an intermediate transfer belt having a surface layer containing a conductive agent (see, for example, Patent Document 3) or an intermediate transfer belt containing a coupling agent having an electron-accepting or electron-donating atomic group in the surface layer. (For example, refer to Patent Document 4).

  In an image forming method using an intermediate transfer body, when the toner image transfer (secondary transfer) between the intermediate transfer body and the final medium (for example, paper) is not performed well, partial image omission, density reduction, and toner consumption Problems such as an increase in

  The improvement in the surface property of the intermediate transfer member described above is to cope with the problem of secondary transferability by adjusting the surface property on the intermediate transfer member side because the final medium of the toner image is generally paper. .

  However, when the intermediate transfer member is hard and the surface energy is low, the inorganic external additive in the developer aggregates and adheres to the photosensitive member, resulting in a problem that comet-like image defects occur in the final image.

The above problem occurs regardless of the surface energy levels of the photosensitive member and the intermediate transfer member, and it has become clear that adjustment of the surface energy of the conventional intermediate transfer member and the photosensitive member cannot cope with this image defect.
JP-A-9-230714 JP-A-9-269676 JP 2001-242725 A JP 2002-328535 A

  The present invention is an electrophotographic image forming method using an intermediate transfer member (hereinafter, a belt-like intermediate transfer member is also referred to as an intermediate transfer belt), and the above-described comet-like image defect (hereinafter also referred to as a dash mark). And an image forming apparatus capable of producing a good electrophotographic image.

  The inventors of the present application consider that the above-mentioned problem is necessary to find a configuration that makes it difficult to attach an external additive of toner that causes comet-like image defects to the surface of the photoreceptor. As a result of examining the whole image forming method using the intermediate transfer member, the present invention was completed.

That is, the subject of this invention is achieved by the structure as described below.
1. At least a charging step for charging the electrophotographic photosensitive member, an exposure step for forming an electrostatic latent image on the charged electrophotographic photosensitive member, and at least a binder resin for the electrostatic latent image formed on the electrophotographic photosensitive member Development step for developing toner image by using toner obtained by adding external additive to colored particles comprising colorant and transfer step for transferring toner image formed on electrophotographic photosensitive member to intermediate transfer member In the image forming method having a cleaning step for removing residual toner on the surface of the electrophotographic photosensitive member, the dispersion force component (γ _S ^d ) of the free energy on the surface of the intermediate transfer member is 40 mN / m or less, and the electrophotography An image forming method, wherein the surface layer of the photoreceptor contains a structural component obtained by reaction curing of a curable compound.
2. 2. The image forming method as described in 1 above, wherein the curable compound comprises a curable compound having three or more functional groups.
3. 3. The image forming method as described in 1 or 2 above, wherein the reaction site equivalent of the curable compound is 1000 or less.
4). At least an electrophotographic photosensitive member, a charging means for charging the electrophotographic photosensitive member, an exposure means for forming an electrostatic latent image on the charged electrophotographic photosensitive member, and an electrostatic latent image formed on the electrophotographic photosensitive member. Development means for developing an image into a toner image using toner obtained by adding an external additive to colored particles comprising at least a binder resin and a colorant, and intermediate transfer of the toner image formed on the electrophotographic photosensitive member In an image forming apparatus having a transfer means for transferring to a body and a cleaning means for removing residual toner on the surface of the electrophotographic photosensitive member, the free energy dispersion force component (γ _S ^d ) on the surface of the intermediate transfer body is 40 mN / lm or less An image forming apparatus, wherein the surface layer of the electrophotographic photoreceptor contains a structural component obtained by reaction curing of a curable compound.

  By using the image forming method of the present invention, it is possible to improve the transfer characteristics of the toner in the image forming method using the intermediate transfer member, to prevent the occurrence of comet-like image defects, and to produce a good toner image without image defects. It became possible to form stably.

  Hereinafter, the present invention will be described in detail.

The image forming method of the present invention includes at least a charging step for charging the electrophotographic photosensitive member, an exposure step for forming an electrostatic latent image on the charged electrophotographic photosensitive member, and a static image formed on the electrophotographic photosensitive member. A developing step of developing an electrostatic latent image into a toner image using a toner obtained by adding an external additive to colored particles composed of at least a binder resin and a colorant; and a toner image formed on the electrophotographic photoreceptor. An image forming method comprising a transfer step of transferring to an intermediate transfer member and a cleaning step of removing residual toner on the surface of the electrophotographic photosensitive member, wherein the free energy dispersive component (γ _S ^d ) on the surface of the intermediate transfer member is 40 mN / m or less, and the surface layer of the electrophotographic photosensitive member contains a structural component obtained by reaction-curing a curable compound.

  By having the above configuration, the present invention can improve the toner transfer characteristics in the image forming method using the intermediate transfer member and can prevent the occurrence of comet-like image defects, and can stably produce a good toner image without image defects. Can be formed.

  Hereinafter, the intermediate transfer member of the present invention will be described.

The intermediate transfer member surface according to the present invention has a free energy dispersive force component (γ _S ^d ) of 40 mN / m or less.

The dispersion force component (γ _S ^d ) of the free energy on the surface of the intermediate transfer member is 40 mN / m or less, preferably 30 mN / m or less and 19 mN / m or more.

  That is, when the surface energy is 40 mN / m or less, moderate adhesion between the intermediate transfer belt and the toner can be obtained, and the factors that cause the secondary transfer property, the middle loss, or the deterioration of the image quality are eliminated. It is estimated that image formation can be performed.

Further, the dispersive force component (γ _S ^d ) of the free energy on the surface of the intermediate transfer member according to the present invention is calculated as follows.

  In general, the surface energy of a solid material is calculated from the contact angle formed when a liquid having a known surface energy is placed on the solid. Specifically, the contact angle formed when this liquid is placed on a solid whose surface energy is to be known is calculated based on Fowkes' theory from the relational expression of the adhesive work.

  The solid and liquid bonding work is expressed by the following relational expression.

W _SL = γ _L (1 + cos θ _SL )
W _SL : Adhesion work of solid sample / liquid sample γ _L : Surface free energy of liquid sample θ _SL : Contact angle of solid sample / liquid sample Here, adhesion work W _SL is _expressed as dispersion force component, dipole force component, hydrogen When considered by decomposing into three components of the bonding component, the adhesion work _WSL is expressed as follows. That is,
W _SL = W _SL ^d + W _SL ^p + W _SL ^h
W _SL ^d : Adhesion work corresponding to the dispersion force component W _SL ^p : Adhesion work corresponding to the dipole force component W _SL ^h : Adhesion work corresponding to the hydrogen bond component Next, the surface free energy of the surface sample of the solid sample is calculated. Considering γ _S , which is also decomposed into the above three components, it is as follows. That is,
^{_{γ S = γ S d + γ}} S p + γ S h
γ _S : surface free energy of solid sample γ _S ^d : surface free energy corresponding to dispersion force component γ _S ^p : surface free energy corresponding to dipole force component γ _S ^h : surface free energy corresponding to hydrogen bond component Liquid When the surface free energy γ _i (= γ _L ) of the sample is also decomposed into the above three components,
γ _i = γ _i ^d + γ _i ^p + γ _i ^h (i = 1, 2, 3)
γ _i : surface free energy of liquid sample γ _i ^d : surface free energy corresponding to dispersion force component γ _i ^p : surface free energy corresponding to dipole force component γ _i ^h : surface free energy corresponding to hydrogen bond component Liquid Specific examples of the surface free energy γ _i of the sample are as shown in Table 1 below. Here, i = 1 is α-bromonaphthalene, i = 2 is methylene iodide, and i = 3 is water.

  Further, the above-described bonding work is assumed to satisfy the following geometric average relational expression.

  From these equations, the following extended Fowkes equation holds.

In the formula, W _S1 represents adhesion work when the liquid sample is α-bromonaphthalene, W _S2 represents methylene iodide, and W _S3 represents adhesion work when the liquid sample is water.

Since W _S1 , W _S2 , and W _S3 are calculated by contact angle measurement and the numerical values in the matrix are known numerical values, γ _S ^d , γ _S ^p , γ are calculated by inverse matrix calculation based on the above relational expression. it is possible to calculate the _S ^h. From the result, the surface energy γ _S of the solid sample can be calculated.

  Next, an image forming apparatus in which the intermediate transfer belt according to the present invention can be used will be described. Examples of the image forming apparatus capable of using the intermediate transfer belt according to the present invention include a copying machine and a laser printer. In particular, an image forming apparatus capable of continuous printing of 500 sheets or more is preferable. In such an apparatus, since a large amount of prints are produced in a short time, an electric field that causes a decrease in image quality such as white spots is easily generated between the intermediate transfer belt and the recording paper due to the influence of accumulated charges. The intermediate transfer belt according to the invention suppresses the image quality deterioration and enables stable secondary transfer.

In the present invention, the characteristic of the dispersion force component (γ _S ^d ) of the free energy of the intermediate transfer member is 40 mN / m or less, and the surface layer of the photoreceptor contains a structural component obtained by reaction-curing a curable compound. If the surface layer is not satisfied at the same time, the primary transferability of the toner image is lowered and a comet-like image defect is likely to occur.

  In order to constitute the above intermediate transfer member, the following intermediate transfer member is used.

  An example of the intermediate transfer belt 2a according to the present invention is shown in FIG. In FIG. 1, 2a is an endless intermediate transfer belt, 20a is a cross section of the intermediate transfer belt, 21a is a base material layer, 22a is an intermediate layer, and 23a is a surface layer.

(A) in FIG. 1 shows an intermediate transfer belt (b) having a single layer configuration, an intermediate transfer belt (c) having a base layer and a surface layer, and a base layer, an intermediate layer and a surface layer. 3 shows an intermediate transfer belt having a multilayer structure.

The base material layer 23a is preferably an endless belt having a volume resistance of the order of 10 ⁶ to 10 ¹² Ω · cm. For example, polycarbonate (PC), polyimide (PI), polyphenylene sulfide (PPS) polyamide imide (PAI), polyvinylidene fluoride (PVDF), etrafluoroethylene-ethylene copolymer (ETFE) and other resin materials, fluororesins, EPDM, NBR, CR, polyurethane and other rubber materials such as carbon are dispersed or ionic A material containing a conductive material is used, and the thickness is set to about 50 to 200 μm in the case of a resin material and about 300 to 700 μm in the case of a rubber material. Further, before forming the surface layer, the surface of the base material may be pretreated by a known surface treatment method such as plasma, flame, or ultraviolet irradiation.

  The intermediate layer 22a is a layer for improving the adhesion between the base material layer 21a and the surface layer 23a, and is provided as necessary.

  Examples of the method for forming the intermediate layer include a method in which a coating solution in which a resin is dissolved in a solvent is applied, and a method in which a resin is directly formed into a film. A method in which a coating solution in which a resin is dissolved in a solvent is applied. The method of forming is preferable.

  Examples of materials that can be used for the intermediate layer 22a include copolymer resins of vinyl chloride, vinyl acetate, and maleic acid, and polyamide resins. Specific examples of the polyamide resin include N-methoxymethylated nylon (hereinafter abbreviated as “nylon 8”), nylon 12, and copolymer nylon.

  The surface layer 23a is provided to satisfactorily transfer the toner image on the photoreceptor to the intermediate transfer belt and from the intermediate transfer belt to the recording medium.

  Next, the surface layer of the intermediate transfer belt will be described.

In order to make the surface of the intermediate transfer belt of the present invention have a free energy dispersive force component (γ _S ^d ) of 40 mN / m or less, a surface layer of an inorganic oxide layer may be formed on the surface layer of the intermediate transfer belt. preferable. By providing such a surface layer on the intermediate transfer member, it is possible not only to achieve the above-mentioned free energy dispersive force component, but also to have a good balance between flexibility and rigidity that cannot be obtained with a single layer configuration. . In the present invention, the above-described base material layer is also referred to as a base material.

The inorganic oxide layer has a thickness 5 to 500 nm, preferably _{10~300nm, SiO 2, Al 2 O} 3, ZrO 2, in particular SiO ₂ is preferably comprises at least one oxide selected from TiO _2, inorganic oxide The material layer is plasma CVD in which a mixed gas of at least the discharge gas and the raw material gas derived from the inorganic oxide layer is turned into plasma to deposit and form a film according to the raw material gas, particularly plasma CVD performed at or near atmospheric pressure It is preferable to form by.

Hereinafter, a case where silicon oxide (SiO ₂ ) is used as the inorganic oxide layer will be described.

  The atmospheric pressure or the pressure in the vicinity thereof is about 20 kPa to 110 kPa, and 93 kPa to 104 kPa is preferable in order to obtain the good effects described in the present invention.

  The apparatus and method will be described below by taking as an example the case where the intermediate transfer member layer is formed by atmospheric pressure plasma CVD.

  FIG. 2 is an explanatory view of a manufacturing apparatus for manufacturing the surface layer of the intermediate transfer member.

  The intermediate transfer body surface layer manufacturing apparatus 2 (direct method in which the discharge space and the thin film deposition region are substantially the same part and is deposited and formed by exposing the plasma to the substrate) forms an inorganic oxide layer on the substrate. Thus, a roll electrode 20 and a driven roller 201 that are wound around an endless belt-like intermediate transfer member 175 and rotated in the direction of the arrow, and a film forming apparatus that forms an inorganic oxide layer on the surface of the substrate. The atmospheric pressure plasma CVD apparatus 3 is used.

  The atmospheric pressure plasma CVD apparatus 3 includes at least one set of fixed electrodes 21 arranged along the outer periphery of the roll electrode 20, a discharge space 23 in which discharge is performed in a region where the fixed electrode 21 and the roll electrode 20 face each other, A mixed gas supply device 24 that generates a mixed gas G of at least a raw material gas and a discharge gas and supplies the mixed gas G to the discharge space 23; a discharge vessel 29 that reduces the inflow of air into the discharge space 23 and the like; A first power supply 25 connected to the fixed electrode 21, a second power supply 26 connected to the roll electrode 20, and an exhaust unit 28 that exhausts the used exhaust gas G ′.

  Here, the second power source 26 may be connected to the fixed electrode 21, and the first power source 25 may be connected to the roll electrode 20.

  The mixed gas supply device 24 supplies, to the discharge space 23, a mixed gas obtained by mixing a raw material gas for forming a film containing silicon oxide and a rare gas such as nitrogen gas or argon gas.

  Further, the driven roller 201 is urged in the direction of the arrow by the tension urging means 202 and applies a predetermined tension to the base material 175. The tension urging means 202 cancels the urging of the tension when the base material 175 is changed, and the base material 175 can be easily changed.

  The first power supply 25 outputs a voltage having a frequency ω1, the second power supply 26 outputs a voltage having a frequency ω2 higher than the frequency ω1, and the electric field in which the frequencies ω1 and ω2 are superimposed on the discharge space 23 by these voltages. V is generated. Then, the mixed gas G is turned into plasma by the electric field V, and a film (inorganic oxide layer) corresponding to the source gas contained in the mixed gas G is deposited on the surface of the substrate 175.

  Here, as another form, one of the roll electrode 20 and the fixed electrode 21 may be connected to the ground, and the power supply may be connected to the other electrode. In this case, it is preferable to use the second power source for the formation of a dense thin film, and is particularly preferable when a rare gas such as argon is used as the discharge gas.

  In addition, it deposits so that an inorganic oxide layer may be piled up in a plurality of fixed electrodes located in the rotation direction downstream side of a roll electrode, and a mixed gas supply device among a plurality of fixed electrodes, and the thickness of an inorganic oxide layer is adjusted. You may do it.

  Further, among the plurality of fixed electrodes, an inorganic oxide layer is deposited by a fixed electrode located on the most downstream side in the rotation direction of the roll electrode and a mixed gas supply device, and another fixed electrode and mixed gas supply device positioned further upstream Thus, other layers such as an adhesive layer for improving the adhesion between the inorganic oxide layer and the substrate may be formed.

  In addition, in order to improve the adhesion between the inorganic oxide layer and the base material, a gas supply for supplying a gas such as argon, oxygen or hydrogen upstream of the fixed electrode for forming the inorganic oxide layer and the mixed gas supply device An apparatus and a fixed electrode may be provided to perform plasma treatment to activate the surface 171a of the base material.

  As described above, the intermediate transfer belt, which is an endless belt, is stretched around a pair of rollers, and one of the pair of rollers serves as one electrode of a pair of electrodes, and the outer peripheral surface of the roller that serves as one electrode At least one fixed electrode which is the other electrode along the outside of the electrode, and an electric field is generated between these pair of electrodes (fixed electrode and roller electrode) under atmospheric pressure or near atmospheric pressure to perform plasma discharge, By adopting a configuration in which a thin film is deposited and formed on the surface of the intermediate transfer member, it is possible to obtain an intermediate transfer member with high transferability, high cleaning properties and durability.

  Below, the form of the various atmospheric pressure plasma CVD apparatus which forms an inorganic oxide layer on a base material is demonstrated in detail.

  Note that FIG. 3 below is mainly extracted from the broken line portion of FIG. 2.

  FIG. 3 is an explanatory diagram of a first manufacturing apparatus that manufactures the surface layer of the intermediate transfer member using plasma.

  With reference to FIG. 3, an example of a first embodiment of an atmospheric pressure plasma CVD apparatus suitably used for forming an inorganic oxide layer will be described.

  As described above, the first atmospheric pressure plasma CVD apparatus 3 is driven to drive and rotate the mixed gas supply device 24, the fixed electrode 21, the first power supply 25, the first filter 25a, the roll electrode 20, and the roll electrode in the arrow direction. Means 20a, a second power source 26, and a second filter 26a. As described above, plasma discharge is performed in the discharge space 23 to excite and excite the mixed gas G in which the raw material gas and the discharge gas are mixed. The mixed gas G1 is exposed to the substrate surface 175a, and an inorganic oxide layer is deposited and formed on the surface. That is, the discharge space is also a thin film formation region.

A first high frequency voltage having a frequency ω ₁ is applied to the fixed electrode 21 from the first power source 25, and a high frequency voltage having a frequency ω ₂ is applied to the roll electrode 20 from the second power source 26. whereby an electric field frequency omega ₂ and is superimposed is generated at the frequency omega ₁ and the electric field strength V ₂ at electric field intensity V ₁ between the fixed electrode 21 and role electrode 20, a current I ₁ to the fixed electrode 21 The current I ₂ flows through the roll electrode 20 and plasma is generated between the electrodes.

The relationship between frequency ω1 and frequency .omega.2, and the relationship between the electric field strength intensity IV that initiates discharge of the electric field intensity _{V 1} and electric field intensity _{V 2,} and discharge gas, at _{ω 1 <ω 2, V 1} ≧ IV > V ₂ or V ₁ > IV ≧ V ₂ is satisfied, and the output density of the second high-frequency electric field is 1 W / cm ² or more.

Since the electric field strength IV for starting the discharge of nitrogen gas is 3.7 kV / mm, the electric field strength V ₁ applied from at least the first power supply 25 is 3.7 kV / mm or more, and the second high frequency power supply The electric field strength V ₂ applied from 60 is preferably 3.7 kV / mm or less.

In addition, as the first power source 25 (high frequency power source) that can be used for the first atmospheric pressure plasma CVD apparatus 3,
Applied power symbol Manufacturer Frequency Product name A1 Shinko Electric 3kHz SPG3-4500
A2 Shinko Electric 5kHz SPG5-4500
A3 Kasuga Electric 15kHz AGI-023
A4 Shinko Electric 50kHz SPG50-4500
A5 HEIDEN Research Laboratories 100kHz * PHF-6k
A6 Pearl Industry 200kHz CF-2000-200k
A7 Pearl Industry 400kHz CF-2000-400k
And the like, and any of them can be used.

As the second power source 26 (high frequency power source),
Applied power supply symbol Manufacturer Frequency Product name B1 Pearl Industry 800kHz CF-2000-800k
B2 Pearl Industry 2MHz CF-2000-2M
B3 Pearl Industry 13.56MHz CF-5000-13M
B4 Pearl Industry 27MHz CF-2000-27M
B5 Pearl Industry 150MHz CF-2000-150M
And the like, and any of them can be used.

  Of the above power supplies, * indicates a HEIDEN Laboratory impulse high-frequency power supply (100 kHz in continuous mode). Other than that, it is a high-frequency power source that can apply only a continuous sine wave.

In the present invention, the power supplied between the opposing electrodes from the first and second power sources supplies power (power density) of 1 W / cm ² or more to the fixed electrode 21 to generate plasma by exciting the discharge gas. To form a thin film. The upper limit value of the power supplied to the fixed electrode 21 is preferably 50 W / cm ² , more preferably 20 W / cm ² . The lower limit is preferably 1.2 W / cm ² . In addition, discharge area (cm < ² >) points out the area of the range which discharge occurs in an electrode.

Further, by supplying power (output density) of 1 W / cm ² or more to the roll electrode 20, it is possible to improve the output density while maintaining the uniformity of the high frequency electric field. Thereby, a further uniform high-density plasma can be generated, and a further improvement in film forming speed and an improvement in film quality can be achieved. Preferably it is 5 W / cm ² or more. The upper limit value of the power supplied to the roll electrode 20 is preferably 50 W / cm ² .

  Here, the waveform of the high-frequency electric field is not particularly limited. There are a continuous sine wave continuous oscillation mode called a continuous mode and an intermittent oscillation mode called ON / OFF intermittently called a pulse mode. Either of them may be adopted, but at least the high frequency supplied to the roll electrode 20 The continuous sine wave is preferable because a denser and better quality film can be obtained.

  In addition, a first filter 25 a is installed between the fixed electrode 21 and the first power supply 25 to facilitate passage of current from the first power supply 25 to the fixed electrode 21, and the second power supply 26. The current from the second power source 26 to the first power source 25 is less likely to pass through, and the second electrode 26 and the second power source 26 are connected between the second electrode 26 and the second power source 26. A filter 26a is installed to facilitate the passage of current from the second power source 26 to the roll electrode 20, ground the current from the first power source 21, and the first power source 25 to the second power source 26. It is designed to make it difficult for current to pass through.

  It is preferable to employ an electrode that can maintain a uniform and stable discharge state by applying a strong electric field as described above to the electrode, and the fixed electrode 21 and the roll electrode 20 have at least a resistance to discharge by a strong electric field. One electrode surface is coated with the following dielectric.

  In the above description, the relationship between the electrode and the power source may be that the second power source 26 is connected to the fixed electrode 21 and the first power source 25 is connected to the roll electrode 20.

  Further, as another form, one electrode may be connected to the ground, and the power source connected to the other electrode is preferably a second power source so that a dense thin film can be formed. This is preferable when a rare gas is used.

  Further, the surface layer 23a of the intermediate transfer body is formed by spraying a surface layer coating solution containing a conductive substance and a reactive compound on the base material layer to form a coating film, and the fluidity of the coating film is lost. After the primary drying, the reactive compound is preferably cured by ultraviolet rays, and further subjected to secondary drying to make the amount of volatile substances in the coating film a specified amount.

  As the resin for the surface layer, a resin obtained by reaction-curing a compound having a curable functional group is preferable.

  Examples of the compound having a curable functional group include thermosetting compounds such as acrylic, phenolic, melamine, alkyd, silicone, epoxy, urethane, and unsaturated polystyrene, vinyl ether, vinyl, A chain polymerization compound having an unsaturated double bond such as styrene and acrylic. These may be used alone or in combination.

  Although an example of the material of the preferable coating liquid for surface layers is shown below, it is not limited to this.

Dipentaerythritol hexaacrylate (KAYARAD DPHA: Nippon Kayaku)
1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184: Ciba Specialty Chemicals)
Antimony-doped tin oxide (T-1: Mitsubishi Materials)
Silica sol (MEK silica sol: Nissan Chemical)
Polytetrafluoroethylene dispersion (KD-500AS: Kitamura Chemical)
Polydimethylsiloxane Methyl ethyl ketone: Methyl isobutyl ketone = 8: 2
The amount of the volatile substance in the intermediate transfer belt defined in the present invention is preferably controlled by the type of solvent used for forming the surface layer, the intensity of UV light, the integrated light quantity, and the drying conditions.

In the present invention, the integrated light quantity (mJ / cm ² ) of ultraviolet light is adjusted by the intensity (mW / cm ² ) of the mercury lamp and the irradiation time.

<Conductive substance>
In the present invention, it is preferable to add a conductive substance to each layer for the purpose of controlling the potential characteristics of the intermediate transfer belt.

  Examples of the conductive substance used in the present invention include a conductive filler and an ionic conductive agent.

  The conductive filler preferably has a number primary average particle size of 5 μm or less, more preferably 0.01 to 1 μm. By setting the average particle size of the conductive filler to 5 μm or less, there is no possibility that the conductive filler is unevenly distributed during film formation, and as a result, there is no variation in the electrical characteristics of the intermediate transfer belt.

  Specific examples of the conductive filler include carbon black and conductive metal oxide.

  Use of carbon black is preferable because electrical characteristics can be achieved with a small amount of use.

  As the carbon black, various existing carbon blacks can be used as long as they have conductivity, and examples thereof include furnace black, acetylene black, thermal black, and channel black.

  The blending amount of carbon black varies depending on the type of carbon black, but is preferably 5 to 40 parts by mass with respect to the entire intermediate transfer belt, and is appropriately added so as to meet the required volume resistivity.

  Examples of the conductive metal oxide include tin oxide, zinc oxide, antimony oxide, indium oxide, potassium titanate, antimony oxide-tin oxide composite oxide (ATO), and indium oxide-tin oxide composite oxide (ITO). Can be used.

  The conductive metal oxide is preferably surface-treated with a silane coupling agent. This treatment is performed by adding and mixing a metal oxide into a silane coupling agent solution dissolved in a suitable solvent, evaporating the solvent and drying. Surface-treated metal oxide (surface-treated or non-treated conductive metal oxide may be referred to as a conductive agent hereinafter) improves compatibility with the polyimide resin, so that the dispersion becomes uniform and the surface The variation in resistivity is further suppressed. The compounding amount of the metal oxide surface-treated with the silane coupling agent is different depending on the type of metal oxide for the same reason as that of the metal oxide not surface-treated. However, it is in the range of 32 to 40 parts by mass, preferably 35 to 38 parts by mass with respect to 100 parts by mass of the resin. Silane coupling agents include vinyltrichlorosilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, and γ-glycidoxypropyltrimethoxy. Silane, γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyl Examples include dimethoxysilane.

Examples of ionic conductive agents include lauryltrimethylammonium, stearyltrimethylammonium, octadodecyltrimethylammonium, dodecyltrimethylammonium, hexadecyltrimethylammonium, dechlorinated fatty acid / dimethylethylammonium salt perchlorate, chlorate, and borofluoric acid. Salts, sulfates, etosulphate salts, cationic surfactants such as quaternary ammonium salts such as benzyl halides such as benzyl bromide and benzyl chloride, aliphatic sulfonates, higher alcohol sulfates , Higher alcohol ethylene oxide addition sulfate ester salt, higher alcohol phosphate ester salt, anionic surfactant such as higher alcohol ethylene oxide addition phosphate ester salt, amphoteric ion surfactant such as various betaines, higher alcohol Lumpur ethylene oxide, polyethylene glycol fatty acid esters, nonionic antistatic agents such antistatic agents such as polyhydric alcohol fatty acid _{esters, LiCF 3 SO 3, NaCl 4} , LiClO 4, LiAsF 6, LiBF 4, NaSCN, KSCN, Lithium, such as NaCl ⁺ Lithium, Na ⁺ , K ^{+ and} other group 1 metal salts, electrolytes such as NH ⁴⁺ salts, Ca ²⁺ such as Ca (ClO ₄ ) ₂ , Ba ^2+, etc. Table 2 Group metal salts and these antistatic agents include those having a group having active hydrogen which reacts with isocyanate such as at least one hydroxyl group, carboxyl group, primary or secondary amine group. Furthermore, with them, complexes of polyhydric alcohols such as 1,4-butanediol, ethylene glycol, polyethylene glycol, propylene glycol, polyethylene glycol and derivatives thereof, or monools such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether The complex of these is mentioned, The 1 type chosen from these or 2 types or more can be used. However, it is not limited to the above-mentioned materials such as other known ion conductive resistance control agents.

  The production method of the intermediate transfer belt according to the present invention is not particularly limited. For example, each layer forming material and its solvent are appropriately blended, and each coating solution is prepared by kneading and stirring with a ball mill or the like. To do. The concentration of the coating solution thus prepared is appropriately set according to the layer thickness. Next, each coating solution is accommodated in a tank, and on the other hand, a shaft made of metal such as aluminum or stainless steel is prepared, and this shaft is vertically placed in a tank in which the coating liquid for the base material layer is accommodated. Put in a standing condition and immerse. At this time, the immersion is repeated several times to form a coating film having a predetermined thickness, and then the shaft is pulled up from the coating solution. Subsequently, the same operation is repeated using the coating liquid of each layer to form a multilayer structure. Next, after drying and removing the solvent, heat treatment (for example, 60 to 150 ° C. × 60 minutes) is performed, and the shaft body is extracted to produce the endless intermediate transfer belt shown in FIG.

  In addition to this dipping method, an intermediate transfer belt can be produced by methods such as extrusion molding, spray coating, inflation, and blow molding.

  In particular, when a polyimide resin is used for the base material layer, for example, a polyamic acid solution obtained by polymerizing a tetracarboxylic dianhydride having a wholly aromatic skeleton and a diamine component is developed in an appropriate manner. Then, the development layer is dried and formed into a film, and the base material layer is obtained by a method of heat-treating the molded product to convert the polyamic acid into an imide. Then, an intermediate transfer belt is produced by sequentially dipping or spray-coating a coating solution constituting another layer on the base material layer.

  When forming a seamless intermediate transfer belt, for example, a method in which a polyamic acid solution is immersed in the outer peripheral surface of a cylindrical mold, a method in which it is applied to the inner peripheral surface, a method in which centrifugation is further performed, or a method in which a casting mold is filled Such as a method of expanding into a ring shape by an appropriate method such as, drying the formed layer into a bell-shaped shape, heat-treating the molded product to convert the polyamic acid into an imide, and recovering from the mold Can be carried out by an appropriate method according to the conventional method (JP-A 61-95361, JP-A 64-22514, JP-A 3-180309, etc.). In forming the seamless belt, an appropriate treatment such as mold release treatment or defoaming treatment can be performed.

The intermediate transfer belt according to the present invention preferably has a surface resistivity of 1 × 10 ¹⁰ to 1 × 10 ¹⁴ Ω / □ on the belt surface. By controlling the surface resistivity within the above range, suppression of local peeling discharge at the post nip portion (where the recording medium and the intermediate transfer belt peel at the secondary transfer portion) due to the action of the conductive fine particles described above is suppressed. Presumed to be assisting. In addition, it is presumed that the pre-nip portion (where the recording medium of the secondary transfer portion and the intermediate transfer body start to contact) also assists in uniformizing the electric field strength, and the effect of gap discharge at the pre-nip portion in the prior art. The influence on the graininess of the image quality that has been a concern is also improved.

  The surface resistivity on the surface of the intermediate transfer belt according to the present invention can be measured based on JIS K6991 using a circular electrode (for example, “HR probe” of High Lester IP manufactured by Mitsubishi Oil Chemical Co., Ltd.). For the method of measuring the surface resistivity of the intermediate transfer belt according to the present invention, reference can be made to, for example, the description in paragraph 0047 and FIG. 7 of JP-A-2001-242725.

The volume resistivity of the intermediate transfer belt according to the present invention is preferably 1 × 10 ⁸ to 1 × 10 ¹² Ω · cm. By setting the volume resistivity within the above range, the electrostatic force between the toners is increased by an electrostatic force that acts to appropriately hold the charge of the unfixed toner image transferred from the intermediate transfer member to the recording medium. It is estimated that the influence of the repulsive force and the fringe electric field near the image edge is suppressed. As a result, the toner image transferred onto the recording medium does not scatter and is expected to form a stable image without being affected by noise due to electrostatic repulsion. In this way, the intermediate transfer belt according to the present invention does not need to worry about the occurrence of toner scattering in addition to preventing the occurrence of image defects.

  The volume resistivity can be measured based on JIS K6991 using a circular electrode (for example, HR probe of Hirester IP manufactured by Mitsubishi Yuka Co., Ltd.) in the same manner as the surface resistivity described above. For a specific method of measuring the volume resistivity, reference can be made to, for example, paragraph 0048 of JP-A-2001-242725 and the description of FIG.

  Next, the electrophotographic photosensitive member according to the present invention will be described.

  The electrophotographic photoreceptor according to the present invention preferably has a structure in which a photosensitive layer and a surface layer (protective layer) are sequentially laminated on a conductive support, and the surface layer is a surface obtained by reaction-curing a compound having a curable functional group. It is a layer.

  Since the electrophotographic photosensitive member of the present invention has the above-described configuration, it is possible to prevent occurrence of comet-like image defects (dash marks) due to toner deposits by combining with the above-described intermediate transfer member. With the image forming method using, the occurrence of voids due to poor transfer can be suppressed, and a good electrophotographic image can be obtained.

  First, description of the surface layer according to the present invention will be given below.

  A compound having a curable functional group (hereinafter also referred to as a curable compound) is described.

  The compound having a curable functional group is a photopolymerization initiator or a catalytic function of a polymerization initiator, generates a radical group, and generates a polymerization reaction by a chain reaction of the radical group. Or a compound capable of forming a crosslinked resin.

  The surface layer is a surface layer obtained by reaction curing of a compound having a curable functional group. A polymerization reaction is generated by a chain reaction of the radical group, and a polymer, that is, a polymer compound or a crosslinked resin is generated. Means surface layer.

Examples of the curable functional group include an acryloyloxy group (CH ₂ ═CHCOO—), a methacryloyloxy group (CH ₂ ═C (CH ₃ ) COO—), an epoxy group, and the like.

  These curable compounds may be used as they are as the coating solution component for the surface layer, but may be polymerized in advance to form a coating solution component for the surface layer.

  Although the example of a curable compound is given to the following, this invention is not limited only to these exemplary compounds.

  The number of Ac groups in the exemplary compound indicates the number of functional groups in the curable compound.

  The above curable compounds are commercially available and can be purchased from Nippon Kayaku Co., Ltd., Toagosei Co., Ltd., Daicel Cytec Co., Ltd. and the like.

  The functional group of the curable compound is preferably bifunctional or higher, and in order to obtain a network-like resin structure, it is preferable to mix trifunctional or higher functional compounds.

  The reaction site equivalent of the curable compound is preferably 1000 or less. Here, the reaction point equivalent is a value obtained by dividing the molecular weight of the curable compound by the number of functional groups (the number of Ac groups). By setting the reaction point equivalent to 1000 or less, the crosslinking density of the surface layer can be increased, adhesion of toner external additives can be prevented, and generation of dash marks can be effectively prevented.

  Examples of the polymerization initiator of the curable compound, that is, the photopolymerization initiator, include benzophenone, Michler ketone, 1-hydroxycyclohexyl-phenyl ketone, thioxanthone, benzobutyl ether, acyloxime ester, dibenzothroben, bisacylphosphine oxide, and the like. be able to.

  A commercial item can also be used for these polymerization initiators. For example, the following compounds are commercially available from Ciba.

  The coating solution solvent for the surface layer is not particularly limited as long as it dissolves the curable compound and the polymerization initiator, and specifically n-butyl alcohol, isopropyl alcohol, ethyl alcohol, methyl alcohol, methyl isobutyl ketone. And methyl ethyl ketone.

  In order to form the surface layer, the surface layer coating solution (the above composition) is applied onto the photosensitive layer, and then first dried to such an extent that the fluidity of the coating film is lost, and then the surface layer is irradiated with ultraviolet rays. A method of curing and performing secondary drying to make the amount of volatile substances in the coating film a specified amount is preferable.

  As a device for irradiating ultraviolet rays, a known device used for curing an ultraviolet curable resin can be used.

The amount of ultraviolet rays (mJ / cm ² ) for curing the resin with ultraviolet rays is preferably controlled by the ultraviolet irradiation intensity and irradiation time.

  The film thickness of the surface layer according to the present invention is 0.5 to 15 μm, preferably 1 to 10 μm.

  Further, the surface layer may contain an antioxidant. The content of the antioxidant is preferably 0.5 to 20% by mass with respect to 100% by mass of the photocurable compound.

  The surface layer preferably contains a metal oxide. By containing a metal oxide, the hardness of the surface layer can be further increased, and the wear of the photoreceptor can be reduced.

  Such metal oxides (metal oxide particles) include transition metal silicon oxides, for example, silica, zinc oxide, titanium oxide, alumina, tin oxide, antimony oxide, indium oxide, bismuth oxide, Fine particles of tin-doped indium oxide, antimony or tantalum-doped tin oxide, zirconium oxide, etc. can be preferably used, but among these, silica, in particular, cost, adjustment of particle size, ease of surface treatment, etc. Titanium oxide, alumina (aluminum oxide) and the like are preferable.

  The size of these metal oxide particles is preferably 5 to 100 nm in terms of number average primary particle size.

  The number average primary particle diameter of the metal oxide particles is magnified 10,000 times by observation with a transmission electron microscope, 300 particles are randomly observed as primary particles, and the measured value is obtained as the number average diameter of the ferret diameter by image analysis. calculate.

  In order to adjust the water absorption rate of the metal oxide particles to a range of 0.1 to 10%, it is preferable to subject the surfaces of these metal oxide particles to a hydrophobic treatment.

  As the hydrophobizing agent, known compounds can be used, and specific examples are given below. These compounds may be used in combination.

  Examples of the titanium coupling agent include tetrabutyl titanate, tetraoctyl titanate, isopropyl triisostearoyl titanate, isopropyl tridecylbenzenesulfonyl titanate, and bis (dioctylpyrophosphate) oxyacetate titanate.

  Examples of silane coupling agents include γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β-vinylbenzylamino. Ethyl-N-γ-aminopropyltrimethoxysilane hydrochloride, hexamethyldisilazane, methyltrimethoxysilane, butyltrimethoxysilane, isobutyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, dodecyl Examples include trimethoxysilane, phenyltrimethoxysilane, o-methylphenyltrimethoxysilane, and p-methylphenyltrimethoxysilane.

  Examples of the silicone oil include dimethyl silicone oil, methylphenyl silicone oil, and amino-modified silicone oil.

  A hydrogen polysiloxane compound may be used as the surface hydrophobizing agent. The molecular weight of the hydrogen polysiloxane compound is generally easily from 1000 to 20000. In particular, when methylhydrogenpolysiloxane is used for the final surface treatment, a good effect can be obtained.

  These hydrophobizing agents are preferably added in an amount of 1 to 40% by mass and more preferably 3 to 30% by mass with respect to the metal oxide particles.

  Hydrophobizing treatment of metal oxide particles is performed by spraying a hydrophobizing agent solution dissolved with alcohol or the like into a cloud-like dispersion of metal oxide particles by stirring or the like, or contacting a vaporized hydrophobizing agent. It can be carried out by a conventionally known method such as a dry process for adhering and adhering, or a wet process in which metal oxide particles are dispersed in a solution and a hydrophobizing agent is added dropwise thereto.

  The content of the metal oxide particles in the surface layer is 5 to 200% by mass, preferably 30 to 150% by mass, and most preferably 50% to 100% by mass of the compound having a photocurable functional group used for the surface layer. It should be used at ˜120% by mass. Within the range of 5 to 200% by mass, the effect of the present invention is excellent, the secondary transferability is improved, the dash marks and voids are improved, the residual potential is increased, the image density is decreased, or the image is flowed. And an excellent electrophotographic image can be obtained.

  Hereinafter, the configuration of the electrophotographic photoreceptor applied to the present invention other than the surface layer will be described.

  The electrophotographic photoreceptor according to the present invention is preferably an organic photoreceptor. An organic photoconductor means an electrophotographic photoconductor formed by providing an organic compound with at least one of a charge generation function and a charge transport function essential for the construction of an electrophotographic photoconductor. It contains all known organic photoreceptors such as a photoreceptor composed of a substance or an organic charge transport material, and a photoreceptor composed of a polymer complex having a charge generation function and a charge transport function.

  The layer structure of the organic photoreceptor of the present invention is basically composed of a photosensitive layer of an intermediate layer, a charge generation layer and a charge transport layer on a conductive support. The charge transport layer may be composed of a plurality of charge transport layers. The uppermost layer is composed of the surface layer described above.

  Hereinafter, a specific configuration of the photoreceptor used in the present invention will be described.

Conductive Support As the conductive support used in the photoreceptor of the present invention, a sheet-like or cylindrical conductive support is used.

  The cylindrical conductive support of the present invention means a cylindrical support necessary for forming an endless image by rotating, and the straightness is in the range of 0.1 mm or less and the deflection is 0.1 mm or less. Certain conductive supports are preferred. Exceeding the range of straightness and shake makes it difficult to form a good image.

As a material for the conductive support, a metal drum such as aluminum or nickel, a plastic drum on which aluminum, tin oxide, indium oxide or the like is deposited, or a paper / plastic drum coated with a conductive substance can be used. The conductive support preferably has a specific resistance of 10 ³ Ωcm or less at room temperature.

  As the conductive support used in the present invention, one having an alumite film that has been sealed on the surface thereof may be used. The alumite treatment is usually performed in an acidic bath such as chromic acid, sulfuric acid, oxalic acid, phosphoric acid, boric acid, sulfamic acid, etc., but anodizing treatment in sulfuric acid gives the most preferable result. In the case of anodizing in sulfuric acid, the sulfuric acid concentration is preferably 100 to 200 g / l, the aluminum ion concentration is 1 to 10 g / l, the liquid temperature is about 20 ° C., and the applied voltage is preferably about 20 V. It is not limited. The average film thickness of the anodized film is usually 20 μm or less, particularly preferably 10 μm or less.

Intermediate Layer In the present invention, it is preferable to provide the above-described intermediate layer having a barrier function between the conductive support and the photosensitive layer.

  The intermediate layer of the present invention preferably contains titanium oxide in the binder resin having a small water absorption rate. The average particle diameter of the titanium oxide particles is preferably in the range of 10 nm to 400 nm in terms of number average primary particle diameter, and is preferably 15 nm to 200 nm. If it is less than 10 nm, the effect of preventing the occurrence of moire by the intermediate layer is small. On the other hand, if it is larger than 400 nm, the titanium oxide particles in the intermediate layer coating solution are likely to settle, resulting in poor uniform dispersibility of the titanium oxide particles in the intermediate layer, and an increase in black spots (black spot image defects). It's easy to do. An intermediate layer coating liquid using titanium oxide particles having a number average primary particle size in the above range has good dispersion stability, and the intermediate layer formed from such a coating liquid has an environmental characteristic in addition to the function of preventing the occurrence of black spots. Is good and has cracking resistance.

  The shape of the titanium oxide particles used in the present invention includes a dendritic shape, a needle shape, a granular shape, and the like. The titanium oxide particles having such a shape are, for example, titanium oxide particles, anatase type, rutile as crystal types. There are types, amorphous types, and the like. Any crystal type may be used, or two or more crystal types may be mixed and used. Among them, the rutile type and granular type are the best.

  The titanium oxide particles of the present invention are preferably surface-treated, and one of the surface treatments is a plurality of surface treatments, and the last surface treatment is a reactive organic in the plurality of surface treatments. Surface treatment using a silicon compound is performed. In addition, at least one of the surface treatments is at least one surface treatment selected from alumina, silica, and zirconia, and finally a surface treatment using a reactive organosilicon compound. It is preferable to carry out.

  Alumina treatment, silica treatment, and zirconia treatment are treatments for precipitating alumina, silica, or zirconia on the surface of titanium oxide particles, and alumina, silica, and zirconia deposited on these surfaces are water of alumina, silica, zirconia Japanese products are also included. The surface treatment of the reactive organosilicon compound means using a reactive organosilicon compound in the treatment liquid.

  In this way, the surface treatment of the titanium oxide particles such as titanium oxide particles is performed at least twice, so that the surface of the titanium oxide particles is uniformly coated (treated), and the surface-treated titanium oxide particles are used as the intermediate layer. When used in the present invention, it is possible to obtain a good photoconductor having good dispersibility of titanium oxide particles such as titanium oxide particles in the intermediate layer and causing no image defects such as black spots.

  Examples of the reactive organosilicon compound include compounds represented by the following general formula (1), but the compound is not limited to the following compounds as long as it is a compound that undergoes a condensation reaction with a reactive group such as a hydroxyl group on the titanium oxide surface.

General formula (1)
(R) _n -Si- (X) _4-n
(In the formula, Si represents a silicon atom, R represents an organic group in which carbon is directly bonded to the silicon atom, X represents a hydrolyzable group, and n represents an integer of 0 to 3.)
In the organosilicon compound represented by the general formula (1), the organic group in which carbon is directly bonded to the silicon represented by R includes alkyl such as methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl and dodecyl. Group, aryl group such as phenyl, tolyl, naphthyl, biphenyl, epoxy-containing group such as γ-glycidoxypropyl, β- (3,4-epoxycyclohexyl) ethyl, γ-acryloxypropyl, γ-methacryloxypropyl (Meth) acryloyl group, hydroxyl group such as γ-hydroxypropyl and 2,3-dihydroxypropyloxypropyl, vinyl group such as vinyl and propenyl, mercapto group such as γ-mercaptopropyl, γ-aminopropyl, Amino-containing groups such as N-β (aminoethyl) -γ-aminopropyl, γ-chloropropyl, , 1,1-tri fluoroalkyl propyl, nonafluorohexyl, halogen-containing groups such as perfluorooctylethyl, other nitro, and cyano-substituted alkyl group. Examples of the hydrolyzable group for X include alkoxy groups such as methoxy and ethoxy, halogen groups, and acyloxy groups.

  Moreover, the organosilicon compound represented by the general formula (1) may be used alone or in combination of two or more.

  Moreover, in the specific compound of the organosilicon compound represented by the general formula (1), when n is 2 or more, a plurality of R may be the same or different. Similarly, when n is 2 or less, the plurality of Xs may be the same or different. Moreover, when using 2 or more types of organosilicon compounds represented by General formula (1), R and X may be the same between each compound, and may differ.

  Moreover, a polysiloxane compound is mentioned as a preferable reactive organosilicon compound used for surface treatment. The polysiloxane compound having a molecular weight of 1000 to 20000 is generally easily available, and has a good function to prevent occurrence of black spots.

  In particular, when methylhydrogenpolysiloxane is used for the final surface treatment, a good effect can be obtained.

Photosensitive layer Charge generation layer The charge generation layer contains a charge generation material (CGM). Other substances may contain a binder resin and other additives as necessary.

  In the organic photoreceptor of the present invention, for example, a phthalocyanine pigment, an azo pigment, a perylene pigment, an azulenium pigment or the like can be used alone or in combination as a charge generating substance.

  When a binder is used as the CGM dispersion medium in the charge generation layer, a known resin can be used as the binder, but the most preferred resins include formal resin, butyral resin, silicone resin, silicone-modified butyral resin, phenoxy resin, and the like. Can be mentioned. The ratio of the binder resin to the charge generating material is preferably 20 to 600 parts by mass with respect to 100 parts by mass of the binder resin. By using these resins, the increase in residual potential associated with repeated use can be minimized. The thickness of the charge generation layer is preferably 0.1 μm to 2 μm.

Charge Transport Layer The charge transport layer contains a charge transport material (CTM) and a binder resin that forms a film by dispersing CTM. Other substances may contain additives such as antioxidants as necessary.

  A known charge transport material (CTM) can be used as the charge transport material (CTM). For example, a triphenylamine derivative, a hydrazone compound, a styryl compound, a benzidine compound, a butadiene compound, or the like can be used. These charge transport materials are usually dissolved in a suitable binder resin to form a layer. Among these, the CTM capable of minimizing the increase in residual potential due to repeated use has a high mobility and an ionization potential difference from the combined CGM of 0.5 (eV) or less, preferably 0 .30 (eV) or less.

  The ionization potential of CGM and CTM is measured with a surface analyzer AC-1 (manufactured by Riken Keiki Co., Ltd.).

  The binder resin used for the charge transport layer (CTL) may be either a thermoplastic resin or a thermosetting resin. For example, polystyrene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, polycarbonate resin, silicone resin, melamine resin, and these resins A copolymer resin containing two or more of the repeating unit structures. In addition to these insulating resins, high molecular organic semiconductors such as poly-N-vinylcarbazole can be used. Of these, polycarbonate resins are most preferred because of their low water absorption and good CTM dispersibility and electrophotographic characteristics.

  The ratio of the binder resin to the charge transport material is preferably 50 to 200 parts by mass with respect to 100 parts by mass of the binder resin.

  The total thickness of the charge transport layers (one or more layers, preferably 1 to 3 layers) is preferably 5 to 25 μm. If the film thickness is less than 5 μm, the charged potential tends to be insufficient, and if it exceeds 25 μm, the sharpness tends to deteriorate.

  Solvents or dispersion media used to form layers such as intermediate layers, charge generation layers, and charge transport layers include n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N, N-dimethylformamide, acetone , Methyl ethyl ketone, methyl isopropyl ketone, cyclohexanone, benzene, toluene, xylene, chloroform, dichloromethane, 1,2-dichloroethane, 1,2-dichloropropane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, trichloroethylene, Tetrachloroethane, tetrahydrofuran, dioxolane, dioxane, methanol, ethanol, butanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, methyl cello Lube, and the like. Although this invention is not limited to these, Dichloromethane, 1, 2- dichloroethane, methyl ethyl ketone, etc. are used preferably. These solvents may be used alone or as a mixed solvent of two or more.

  Next, as a coating processing method for manufacturing the organic photoreceptor, a coating processing method such as dip coating, spray coating, circular amount regulation type coating, etc. is used. In order to prevent dissolution as much as possible, it is preferable to use a coating processing method such as spray coating or circular amount regulation type (circular slide hopper type is a typical example) coating in order to achieve uniform coating processing. It is most preferable to use the circular amount regulation type coating method for the surface layer. The circular amount regulation type coating is described in detail in, for example, Japanese Patent Application Laid-Open No. 58-189061.

Toner used in the present invention Next, the toner used in the present invention will be described.

  The method for producing colored particles (hereinafter also referred to as toner particles) that are toner base particles is not particularly limited, but is preferably produced by solid-liquid separation of toner particles from a liquid. Although it can be produced from a toner particle dispersion prepared by any of the suspension polymerization method, the emulsion association method, the dissolution suspension method, etc., the emulsion polymerization has a sharp particle size distribution, excellent images, and a high developer life. Those produced by the association method are particularly preferred.

  Hereinafter, a method for producing a toner particle dispersion by an emulsion polymerization association method will be described.

  A method for producing a toner particle dispersion by emulsion polymerization is a method for forming toner particles in an aqueous medium, and is disclosed in, for example, JP-A-2002-351142.

  In addition, the resin particles disclosed in JP-A-5-265252, JP-A-6-329947, and JP-A-9-15904 are salted out / fused in an aqueous medium to produce a toner particle dispersion. A method can be mentioned.

  Specifically, after resin particles are dispersed in water using an emulsifier, a coagulant having a critical coagulation concentration or higher is added for salting out, and at the same time, heat fusion is performed at or above the glass transition temperature of the formed polymer itself. Gradually grow the particle size while forming fused particles, stop the particle size growth by adding a large amount of water when the desired particle size is reached, and further smooth the particle surface while heating and stirring The shape is controlled to prepare a toner particle dispersion. Here, a solvent that is infinitely soluble in water, such as alcohol, may be added simultaneously with the flocculant.

  Examples of the aqueous medium include, but are not particularly limited to, water, methanol, ethanol, isopropanol, butanol, 2-methyl-2-butanol, acetone, methyl ethyl ketone, tetrahydrofuran, or a mixture thereof. . A suitable toner can be selected from among these.

  Examples of the organic solvent include toluene, xylene, or a mixture thereof, but are not particularly limited.

  The toner according to the present invention is used by adding so-called external additives to the toner particles for the purpose of improving fluidity and improving cleaning properties. These external additives are not particularly limited, but at least inorganic particles are used.

Inorganic particles Examples of the inorganic particles that can be used as the toner external additive include conventionally known particles.

  Specifically, fine particles of silica, titanium oxide, alumina, tin oxide, magnesium oxide, and zinc oxide can be preferably used. These inorganic particles are preferably hydrophobic.

  Specific examples of the silica powder include commercially available products R-805, R-976, R-974, R-972, R-812, R-809 manufactured by Nippon Aerosil Co., Ltd., HVK-2150 manufactured by Hoechst Co., Ltd. H-200, commercially available products manufactured by Cabot Corporation TS-720, TS-530, TS-610, H-5, MS-5 and the like can be mentioned.

  Specific examples of the titanium oxide fine particles include, for example, commercial products T-805 and T-604 manufactured by Nippon Aerosil Co., Ltd., and commercial products MT-100S, MT-100B, MT-500BS, MT-600 manufactured by Teika Co., Ltd. MT-600SS, JA-1, commercial products manufactured by Fuji Titanium Co., Ltd. TA-300SI, TA-500, TAF-130, TAF-510, TAF-510T, commercial products IT-S, IT- manufactured by Idemitsu Kosan Co., Ltd. OA, IT-OB, IT-OC, etc. are mentioned.

  Specific examples of the alumina fine particles include commercial products RFY-C and C-604 manufactured by Nippon Aerosil Co., Ltd., and commercial products TTO-55 manufactured by Ishihara Sangyo Co., Ltd.

  The number average particle diameter of the inorganic particles is 1 to 100 nm, preferably 3 to 30 nm.

  The addition amount of the external additive is preferably about 0.2 to 5.0% by mass with respect to the toner mass.

  Examples of the apparatus for adding and mixing the external additive into the toner particles include various known mixing apparatuses such as a turbuler mixer, a Henschel mixer, a nauter mixer, and a V-type mixer.

  The toner according to the present invention preferably has a particle size of 3.0 to 8.0 μm. By setting the particle diameter of the toner within this range, a toner image having a high density and no high sharpness can be obtained.

  In the present invention, the particle diameter of the toner is a volume-based median diameter (volume D50% diameter).

Measurement of volume-based median diameter of toner (volume D50% diameter) Measurement and calculation using a device in which a computer system for data processing (Beckman Coulter) is connected to Coulter Multisizer III (Beckman Coulter) To do.

  As a measurement procedure, 0.02 g of toner is blended with 20 ml of a surfactant solution (for example, a surfactant solution obtained by diluting a neutral detergent containing a surfactant component 10 times with pure water for the purpose of dispersing the toner). After that, ultrasonic dispersion is performed for 1 minute to prepare a toner dispersion. This toner dispersion is injected into a beaker containing ISOTON II (manufactured by Beckman Coulter, Inc.) in a sample stand with a pipette until a measurement concentration of 5 to 10% is reached, and the measuring machine count is set to 2500. To do. An aperture diameter of 50 μm was used.

Developer The developer used in the development step may be a one-component developer or a two-component developer.

  In the case of a one-component developer, a non-magnetic one-component developer or a magnetic one-component developer containing about 0.1 to 0.5 μm of magnetic particles in the toner can be used. it can.

  The two-component developer is prepared by mixing 3 to 20 parts by mass of toner with 100 parts by mass of the carrier. As the magnetic particles of the carrier, conventionally known materials such as metals such as iron, ferrite and magnetite and alloys of these metals with metals such as aluminum and lead can be used, and ferrite particles are particularly preferable. The magnetic particles preferably have a volume average particle diameter of 15 to 100 μm, more preferably 25 to 80 μm.

  The image forming apparatus in which the intermediate transfer belt according to the present invention can be used is not particularly limited, and a monochrome image forming apparatus that forms an image with monochromatic toner, or a toner image on an image carrier is sequentially transferred to the intermediate transfer belt. Examples thereof include a color image forming apparatus and a tandem color image forming apparatus in which a plurality of image carriers for each color are arranged in series on an intermediate transfer member.

  FIG. 4 is a cross-sectional configuration diagram showing a color image forming apparatus as an embodiment of the image forming apparatus of the present invention.

  This image forming apparatus is called a tandem color image forming apparatus, and includes a plurality of sets of image forming units 10Y, 10M, 10C, and 10K, an endless belt-shaped intermediate transfer belt unit 7 as a transfer unit, and a recording member P. An endless belt-shaped sheet feeding and conveying means 21 and a belt type fixing device 24 as a fixing means. A document image reading device SC is disposed on the upper part of the main body A of the image forming apparatus.

  As one of the different color toner images formed on each photoconductor, an image forming unit 10Y that forms a yellow image includes a drum-shaped photoconductor 1Y as a first image carrier, and the photoconductor 1Y. A charging unit 2Y, an exposure unit 3Y, a developing unit 4Y, a primary transfer roller 5Y as a primary transfer unit, and a cleaning unit 6Y are arranged around the periphery. In addition, an image forming unit 10M that forms a magenta image as another different color toner image is a drum-shaped photoconductor 1M as a first image carrier, and is arranged around the photoconductor 1M. The charging unit 2M, the exposure unit 3M, the developing unit 4M, the primary transfer roller 5M as the primary transfer unit, and the cleaning unit 6M are included. In addition, an image forming unit 10C that forms a cyan image as another different color toner image includes a drum-shaped photoconductor 1C as a first image carrier, and around the photoconductor 1C. A charging unit 2C, an exposure unit 3C, a developing unit 4C, a primary transfer roller 5C as a primary transfer unit, and a cleaning unit 6C are disposed. In addition, an image forming unit 10K that forms a black image as one of other different color toner images is disposed around a drum-shaped photoconductor 1K as a first image carrier and the photoconductor 1K. A charging unit 2K, an exposure unit 3K, a developing unit 4K, a primary transfer roller 5K as a primary transfer unit, and a cleaning unit 6K.

  The endless belt-shaped intermediate transfer belt unit 7 includes an endless belt-shaped intermediate transfer body 70 as a second image carrier having a semiconductive endless belt shape that is wound around a plurality of rollers and is rotatably supported.

  The respective color images formed by the image forming units 10Y, 10M, 10C, and 10K are sequentially transferred onto the rotating endless belt-shaped intermediate transfer belt 70 by the primary transfer rollers 5Y, 5M, 5C, and 5K, and are combined. A colored image is formed. A recording member P such as paper as a recording medium accommodated in the paper feeding cassette 20 is fed by the paper feeding / conveying means 21, passes through a plurality of intermediate rollers 22 A, 22 B, 22 C, 22 D, and registration rollers 23, and is secondary. A color image is transferred onto the recording member P at a time by being conveyed to a secondary transfer roller 5A as a transfer means. The recording member P to which the color image has been transferred is fixed by the belt-type fixing device 24, is sandwiched between the discharge rollers 25, and is placed on the discharge tray 26 outside the apparatus.

  On the other hand, after the color image is transferred to the recording member P by the secondary transfer roller 5A, the residual toner is removed by the cleaning means 6A from the endless belt-shaped intermediate transfer belt 70 from which the recording member P is separated in curvature.

  During the image forming process, the primary transfer roller 5K is always in pressure contact with the photoreceptor 1K. The other primary transfer rollers 5Y, 5M, and 5C are in pressure contact with the corresponding photoreceptors 1Y, 1M, and 1C, respectively, only during color image formation.

  The secondary transfer roller 5A comes into pressure contact with the endless belt-shaped intermediate transfer belt 70 only when the recording member P passes through the secondary transfer roller 5A and secondary transfer is performed.

  Further, the housing 8 can be pulled out from the apparatus main body A through the support rails 82L and 82R.

  The housing 8 includes image forming units 10Y, 10M, 10C, and 10K, and an endless belt-shaped intermediate transfer belt unit 7.

  The image forming units 10Y, 10M, 10C, and 10K are arranged in tandem in the vertical direction. An endless belt-shaped intermediate transfer belt unit 7 is disposed on the left side of the photoreceptors 1Y, 1M, 1C, and 1K in the figure. The endless belt-shaped intermediate transfer belt unit 7 includes an endless belt-shaped intermediate transfer belt 70 that can be rotated by winding rollers 71, 72, 73, 74, and 76, primary transfer rollers 5Y, 5M, 5C, and 5K, and a cleaning unit. 6A.

  The image forming units 10Y, 10M, 10C, and 10K and the endless belt-shaped intermediate transfer belt unit 7 are integrally pulled out from the main body A by the drawer operation of the housing 8.

  In this way, toner images are formed on the photoreceptors 1Y, 1M, 1C, and 1K by charging, exposure, and development, and the toner images of the respective colors are superimposed on the endless belt-shaped intermediate transfer belt 70, and are collectively applied to the recording member P. The image is transferred and fixed by a belt-type fixing device 24 by pressing and heating. The photoreceptors 1Y, 1M, 1C, and 1K after transferring the toner image to the recording member P are cleaned with the cleaning device 6A to remove the toner remaining on the photoreceptor, and then the above-described charging, exposure, and development cycle. The next image formation is performed.

  The recording member P used in the present invention is a support for holding a toner image, and is usually called an image support, a transfer material, or transfer paper. Specific examples include various recording members such as plain paper from thin paper to thick paper, coated printing paper such as art paper and coated paper, commercially available Japanese paper and postcard paper, plastic film for OHP, and cloth. It is done.

  Examples according to the present invention will be described below, but the present invention is not limited to the following examples. In addition, the mass part in the following sentence represents the mass part of monomer conversion or solid content conversion other than normal mass part.

<Production of intermediate transfer belt>
(Preparation of base material layer 1 (intermediate transfer belt 1))
Polyphenylene sulfide resin (E2180: manufactured by Toray Industries, Inc.) 100 parts by mass Carbon black (Furnace # 3030B: manufactured by Mitsubishi Chemical Corporation) 16 parts by mass Polyacrylonitrile / styrene graphite product of ethylene / glycidyl methacrylate copolymer (Mn> 10000) (Modiper A4400: Japan (Made by Yushi Co., Ltd.)
1 part by mass Calcium montanate 0.2 part by mass The above materials were put into a single screw extruder and melt kneaded to obtain a resin mixture. At the tip of the single screw extruder, an annular die having a slit-like seamless belt-shaped discharge port was attached, and the kneaded resin mixture was extruded into a seamless belt shape. The extruded seamless belt-shaped resin mixture is extrapolated to a cylindrical cooling cylinder provided at the discharge destination, cooled, and solidified to form a seamless cylindrical “base layer 1 (intermediate transfer belt 1)”. Obtained. The base material layer 1 had a thickness of 105 μm and a Young's modulus of 1000 MPa.

(Preparation of base material layer 2 (intermediate transfer belt 2))
N-methyl-2-pyrrolidone (NMP) solution of polyamic acid composed of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) and p-phenylenediamine (PDA) (European made by Ube Industries) Oxidized carbon black (SPECIALBLACK4 (manufactured by Degussa, pH 3.0, volatile content: 14.0%)) is 23 parts by mass with respect to 100 parts by mass of the polyimide resin solids (solid content 18% by mass). In addition, using a collision type disperser (GeanusPY made by Seanas), with a pressure of 200 MPa, a minimum area of 1.4 mm ² is collided after being divided into two parts, and again through a path divided into two parts, mixed five times, A polyamic acid solution containing carbon black for the base material layer was prepared.

  A polyamic acid solution containing carbon black is applied to the inner surface of the cylindrical mold to 0.5 mm via a dispenser, rotated at 1500 rpm for 15 minutes to form a spread layer having a uniform thickness, and then rotated at 250 rpm, Hot air at 60 ° C. was applied for 30 minutes from the outside of the mold, and then heated at 150 ° C. for 60 minutes. Thereafter, the temperature was raised to 360 ° C. at a rate of 2 ° C./min, and further heated at 360 ° C. for 30 minutes to remove the solvent, remove dehydrated ring-closing water, and complete the imide conversion reaction. Thereafter, the temperature was returned to room temperature and peeled off from the mold to obtain a desired endless belt-like “base material layer 2 (intermediate transfer belt 2)”. The base material layer had a thickness of 100 μm and a Young's modulus of 3000 MPa.

<Preparation of Intermediate Transfer Belt 3>
The following surface layer 3 was formed on the substrate of the intermediate transfer belt 2 to produce the intermediate transfer belt 3.

The surface layer 3 of the SiO ₂ layer was formed on the substrate using tetraethoxysilane as a source gas with a plasma CVD apparatus shown in FIG. 3 (direct method) under atmospheric pressure. Film thickness = 20nm
<Preparation of Intermediate Transfer Belt 4>
The following surface layer 4 was formed on the substrate of the intermediate transfer belt 2 to produce the intermediate transfer belt 4.

Under atmospheric pressure, the surface layer 4 of the SiO ₂ layer was formed on the base material using tetraethoxysilane as a source gas by an atmospheric pressure plasma CVD apparatus shown in FIG. 3 (direct method). Film thickness = 150nm
<Preparation of Intermediate Transfer Belt 5>
(The following surface layer 5 is formed on the intermediate transfer belt 1)
Dipentaerythritol hexaacrylate (KAYARAD DPHA: Nippon Kayaku) 100 parts by mass 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184: Ciba Specialty Chemicals) 1 part by mass Antimony-doped tin oxide (T-1: Mitsubishi Materials) 50 Mass parts Silica sol (MEK Silica sol: Nissan Chemical) 20 parts by mass Polytetrafluoroethylene dispersion (KD-500AS: Kitamura Chemical) 30 parts by mass Polydimethylsiloxane 1 part by mass Methyl isobutyl ketone: methyl ethyl ketone = 8: 2 1500 parts by mass The above surface The coating composition for layers was mixed and dissolved to prepare a surface layer coating solution. This coating solution is spray-coated on the base material layer 1 and then subjected to primary drying in a drying apparatus at 30 ° C. for 30 minutes, and then integration of 2000 mJ / cm ² with a mercury lamp having an ultraviolet intensity of 100 mW / cm ^2. Curing was performed by irradiating the light amount, and further, secondary drying was performed in a drying apparatus at 80 ° C. for 60 minutes to form a surface layer 6, thereby producing “intermediate transfer belt 5”.

<Preparation of Intermediate Transfer Belt 6>
An intermediate transfer belt 6 was prepared in the same manner except that polydimethylsiloxane was removed from the coating composition for the surface layer of the intermediate transfer belt 5.

<Preparation of Intermediate Transfer Belt 7>
An intermediate transfer belt 7 was prepared in the same manner except that dipentaerythritol hexaacrylate of the coating composition for the surface layer of the intermediate transfer belt 5 was changed to the exemplified compound (33).

  In the following, examples of production of the photoreceptor are given. In the following text, “part” means “part by mass”.

Production of Photoreceptor 1 Photoreceptor 1 was produced as follows.

  The surface of the cylindrical aluminum support was cut to prepare a conductive support having a surface roughness Rz = 1.5 (μm).

<Intermediate layer>
A dispersion having the following composition was diluted twice with the same mixed solvent, allowed to stand overnight, and then filtered (filter; rigesh mesh 5 μm filter manufactured by Nippon Pole Co., Ltd.) to prepare an intermediate layer coating solution.
Polyamide resin CM8000 (manufactured by Toray Industries, Inc.) 1 part titanium oxide SMT500SAS (manufactured by Teika) 3 parts methanol 10 parts Dispersion was carried out for 10 hours in a batch mode using a sand mill as a disperser.

  It apply | coated by the dip coating method so that it might become a dry film thickness of 2 micrometers on the said support body using the said coating liquid.

<Charge generation layer>
Charge generation material: titanyl phthalocyanine pigment (a titanyl phthalocyanine pigment having a maximum diffraction peak at a position of at least 27.3 ° ± 0.2 by Cu-Kα characteristic X-ray diffraction spectrum measurement) 20 parts polyvinyl butyral resin (# 6000-C : Manufactured by Denki Kagaku Kogyo Co., Ltd.) 10 parts t-butyl acetate 700 parts 4-methoxy-4-methyl-2-pentanone 300 parts were mixed and dispersed for 10 hours using a sand mill to prepare a charge generation layer coating solution. This coating solution was applied onto the intermediate layer by a dip coating method to form a charge generation layer having a dry film thickness of 0.3 μm.

<Charge transport layer>
Charge transport material (4,4′-dimethyl-4 ″-(β-phenylstyryl)
Triphenylamine) 225 parts Binder: Polycarbonate (Z300: Mitsubishi Gas Chemical Co., Ltd.) 300 parts Antioxidant (Irganox 1010: Nihon Ciba Geigy Co., Ltd.) 6 parts Dichloromethane 2000 parts Silicon oil (KF-54: Shin-Etsu Chemical Co., Ltd.) 1 part Were mixed and dissolved to prepare a charge transport layer coating solution. A charge transport layer having a dry film thickness of 20 μm was formed on the charge generation layer using the circular slide hopper coater.

<Surface layer>
Metal oxide particles (number average particle size 10 nm, hydrophobized silica particles) 5 parts Compound having curable functional group (Exemplary Compound No. 17) 20 parts Polymerization initiator (1-hydroxycyclohexyl (phenyl) methanone) 1 part Isopropyl alcohol 40 parts The above components were mixed and stirred, and sufficiently dissolved and dispersed to prepare a surface layer coating solution. A surface layer was applied to the photoreceptor on which the coating solution had been prepared up to the charge transport layer using a circular slide hopper coater. After coating, after drying at 110 ° C. for 20 minutes (solvent drying step S3), ultraviolet rays were irradiated for 1 minute using a high-pressure mercury lamp (ultraviolet curing step S4) to obtain a surface layer having a dry film thickness of 3.0 μm.

Production of photoconductors 2 to 7 The same applies except that the metal oxide particles (hydrophobized one) on the surface layer of photoconductor 1 and the compound having a photocurable functional group are changed as shown in Table 3 below. Thus, photoreceptors 2 to 7 were produced.

Production of Photoreceptor 8 Photoreceptor 8 was produced in the same manner as in production of photoreceptor 1 except that the surface layer was removed.

[Evaluation of photoconductor]
The produced “intermediate transfer belts 1 to 7 and photoreceptors 1 to 8” were combined as shown in Table 3 below, and evaluated as follows.

  The combination of each intermediate transfer belt and photoconductor is equipped with a bizhub C250 (laser exposure / reverse development / intermediate transfer tandem color compound machine) manufactured by Konica Minolta Business Technologies Co., Ltd. Set to -450 V, cyan color with a printing rate of 50% before and after printing 1000 A4 full-color images (person images against a colorful amusement park) in a high-temperature, high-humidity environment (30 ° C, 80% RH) A halftone image was printed, and the halftone image was evaluated according to the following criteria.

"Transfer rate"
The transfer rate (%) of the intermediate transfer member was determined by the following formula.

Transfer rate of intermediate transfer member (%) = {1− (mass of residual toner of intermediate transfer member / mass of toner attached to intermediate transfer member)} × 100
The transfer rate is practically 90% or more, and less than 90% is unacceptable.

"Dash Mark"
The dash marks were evaluated according to the following criteria in the same manner except that the high temperature and high humidity environment (30 ° C., 80% RH) was replaced with the low temperature and low humidity (10 ° C., 20% RH) under the above evaluation conditions.

A: Dash mark nuclei are not seen on the photoconductor, and no dash marks are generated on halftone images (good)
○: Dash mark nuclei are seen on the photoreceptor, but no dash marks are generated in the halftone image (no problem in practical use)
×: Dash mark nuclei are seen on the photoconductor, and dash marks are also generated in halftone images (practical problems)
"Evaluation of hollowness"
Before and after the printing of the 1000 full-color images, the evaluation was made with a cyan grid pattern image.

Evaluation criteria are ◎: No voids are observed.

  ○: Occurrence of voids is slight, and it is slightly visible with the naked eye.

  X: A void occurs and is clearly visible with the naked eye.

  The evaluation results are shown in Table 4.

  From Table 4, the combination of the intermediate transfer belt and the photoconductor of the present invention has obtained good results in each evaluation item, whereas the combination of the intermediate transfer belt and the photoconductor of the comparative example is one of the evaluation items. Thus, it is found that the evaluation is not sufficiently practical.

It is a schematic diagram showing an example of a layer structure of an intermediate transfer belt according to the present invention. It is explanatory drawing of the manufacturing apparatus which manufactures the surface layer of an intermediate transfer body. It is explanatory drawing of the 1st manufacturing apparatus which manufactures the surface layer of an intermediate transfer body with plasma. 1 is a diagram illustrating an example of an image forming apparatus that can use an intermediate transfer belt according to the present invention.

Explanation of symbols

2a endless intermediate transfer belt 20a intermediate transfer belt 21a surface layer 22a intermediate layer 23a base material layer 2 intermediate transfer body manufacturing apparatus 3 atmospheric pressure plasma CVD apparatus 4 atmospheric pressure plasma apparatus 20 roll electrode 21 fixed electrode 23 discharge space 24 mixed gas Supply device 25 First power source 26 Second power source 41 Thin film forming region 117 Secondary transfer roller 170 Intermediate transfer belt 175 Base material 176 Inorganic oxide layer 201 Driven roller 10Y, 10M, 10C, 10K Image forming unit 1Y, 1M, 1C, 1K photoconductor 2Y, 2M, 2C, 2K charging means 3Y, 3M, 3C, 3K exposure means 4Y, 4M, 4C, 4K developing means

Claims (4)

At least a charging step for charging the electrophotographic photosensitive member, an exposure step for forming an electrostatic latent image on the charged electrophotographic photosensitive member, and at least a binder resin for the electrostatic latent image formed on the electrophotographic photosensitive member Development step for developing toner image by using toner obtained by adding external additive to colored particles comprising colorant and transfer step for transferring toner image formed on electrophotographic photosensitive member to intermediate transfer member In the image forming method having a cleaning step for removing residual toner on the surface of the electrophotographic photosensitive member, the dispersion force component (γ _S ^d ) of the free energy on the surface of the intermediate transfer member is 40 mN / m or less, and the electrophotography An image forming method, wherein the surface layer of the photoreceptor contains a structural component obtained by reaction curing of a curable compound. The image forming method according to claim 1, wherein the curable compound includes a curable compound having three or more functional groups. The image forming method according to claim 1, wherein a reaction point equivalent of the curable compound is 1000 or less. At least an electrophotographic photosensitive member, a charging means for charging the electrophotographic photosensitive member, an exposure means for forming an electrostatic latent image on the charged electrophotographic photosensitive member, and an electrostatic latent image formed on the electrophotographic photosensitive member. Development means for developing an image into a toner image using toner obtained by adding an external additive to colored particles comprising at least a binder resin and a colorant, and intermediate transfer of the toner image formed on the electrophotographic photosensitive member In an image forming apparatus having a transfer means for transferring to a body and a cleaning means for removing residual toner on the surface of the electrophotographic photosensitive member, the free energy dispersion force component (γ _S ^d ) on the surface of the intermediate transfer body is 40 mN / lm or less An image forming apparatus, wherein the surface layer of the electrophotographic photoreceptor contains a structural component obtained by reaction curing of a curable compound.

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