JP2006189745A - Intermediate transfer body and image forming apparatus using the intermediate transfer body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intermediate transfer body which can suppress flying-off of toner in a state where the volume resistivity of the intermediate transfer body is high when primary transfer and secondary transfer are performed using a transfer electric field, and from which charges generated by the transfer electric field are easily eliminated, and to provide an image forming apparatus which has the advantage that image defects due to flying-off of toner (blur) is remarkably little and a high-quality transferred image can be stably obtained, the advantage being difficult to be realized in a conventional intermediate transfer body, by disposing such an intermediate transfer body and a charge eliminating means to eliminate charges from the intermediate transfer body. <P>SOLUTION: The intermediate transfer body includes a substrate and a surface layer disposed on the substrate, wherein the surface layer is a photoconductive layer. The image forming apparatus is equipped with the intermediate transfer body and a photo-charge eliminating means to eliminate charges from a surface of the intermediate transfer body by photoirradiation after transferring a toner image formed on the surface of the intermediate transfer body to a transfer material. <P>COPYRIGHT: (C)2006,JPO&amp;NCIPI

Description

  The present invention relates to an intermediate transfer member used in an image forming apparatus using an electrophotographic system such as a copying machine or a printer, and an image forming apparatus using the intermediate transfer member.

In an image forming apparatus using an electrophotographic method, first, a uniform charge is formed on the surface of an image carrier made of a photoconductive photoreceptor made of an inorganic or organic material, and the image signal is modulated with a laser beam or the like. After the electric image is formed, the electrostatic image is developed with a charged toner, and a visualized toner image is formed. Then, the toner image is electrostatically transferred to a recording material such as a recording paper via an intermediate transfer member or directly, and the transferred toner image is fixed on the recording material, thereby obtaining a desired reproduced image. Is obtained.
In particular, there is known an image forming apparatus that employs a system in which a toner image formed on the image carrier is primarily transferred to an intermediate transfer member, and further, a toner image on the intermediate transfer member is secondarily transferred to a recording material ( For example, see Patent Document 1.)

In the image forming apparatus employing the intermediate transfer body method, as the material used for the intermediate transfer body, a material in which a filler such as carbon or a metal compound is dispersed as a conductive agent in a polymer material is used. Polycarbonate resin, PVDF (polyvinylidene fluoride), polyalkylene phthalate, blend material of PC (polycarbonate) / PAT (polyalkylene terephthalate), ETFE (ethylene tetrafluoroethylene copolymer) / PC, ETFE / PAT, PC / PAT The proposal which uses the electroconductive endless belt of thermoplastic resins, such as a blend material, is made | formed (for example, refer patent documents 2-7). In addition, an intermediate transfer belt in which a conductive filler is dispersed in a polyimide resin excellent in mechanical properties and heat resistance has been proposed (see, for example, Patent Documents 8 and 9).
It is known that there is a close relationship as described below between the volume resistivity of such an intermediate transfer member and the image quality of the toner image.

(When the volume resistivity ρv of the intermediate transfer member is low)
It is known that when the volume resistivity ρv of the intermediate transfer member is too low (ρv ≦ 10 ⁸ Ωcm), toner splatters during transfer and the image quality deteriorates (see, for example, Patent Document 10). When the volume resistivity of the intermediate transfer member is too low, the transfer electric field and the transfer current due to the primary transfer roll cause the transfer electric field to be easily applied to the area without the toner layer, thereby expanding the transfer area. This is thought to be due to splattering and being transferred.

(When the volume resistivity of the intermediate transfer member is intermediate)
As an intermediate transfer member of an image forming apparatus that is currently in practical use, one having an intermediate volume resistivity (10 ⁸ Ωcm ≦ ρv ≦ 10 ¹⁴ Ωcm) is used. In such an image forming apparatus, the charged charge is appropriately attenuated by the semiconductivity of the intermediate transfer member. In other words, the average value of the volume resistivity of the intermediate transfer member is in a range where the charged charges are appropriately attenuated (volume resistivity is in an appropriate range), so that image formation is continuously performed without using a neutralizing member. Can do.

However, even if the average value of the volume resistivity of the intermediate transfer member is in the appropriate range (the range in which the charged charge is appropriately attenuated), in such an intermediate transfer member, the primary transfer roll described above is used. Due to the action of the transfer electric field and the transfer current, the transfer electric field is easily applied to the area without the toner layer, so that the transfer area widens, and there is a problem that the toner is scattered and transferred by the action. In addition, in order to obtain high-quality transfer image quality in recent years, there is a tendency for toner to use a spherical toner having a small diameter, and the toner is easily moved by a transfer electric field because the toner is reduced in diameter and spherical. Therefore, the problem that the toner scatters easily occurs. Furthermore, the above intermediate transfer member has the following problems.
That is, when a filler such as carbon or a metal compound is dispersed in a polymer resin, the resistance variation in the intermediate transfer body due to the dispersed state of the filler is as large as about one digit or more, and a slight high between the filler and the filler. For example, the resistance of the intermediate transfer member is lowered with time due to dielectric breakdown of the molecular resin portion or rearrangement of the filler due to energization. As described above, when printing is repeated, there is a problem that the volume resistivity of the intermediate transfer member departs from the range of good volume resistivity over time or the image quality is deteriorated.

(When the volume resistivity ρv of the intermediate transfer member is high)
When the volume resistivity ρv of the intermediate transfer member is high (ρv> 10 ¹⁴ Ωcm), the charge retention property of the intermediate transfer member in the toner image region increases, and an electric field necessary for transfer can be appropriately applied to the toner. it can. On the other hand, since the charge transfer on the surface of the intermediate transfer member in the adjacent non-image portion and the inside thereof is reduced, toner transfer to this region hardly occurs in the primary and secondary transfer. As a result, when the volume resistivity of the intermediate transfer member is high, a toner-formed image with good image quality can be obtained with less toner scattering. However, in this case, a process for removing the charge accumulated on the intermediate transfer member after toner transfer is required, and it is difficult to uniformly remove the intermediate transfer member in the charge removal step. The reason why it has not been put into practical use is as follows.

In the case of providing the static elimination step, it is easily assumed that a corotron or a static elimination roll is used as the static elimination member. When neutralizing the intermediate transfer member using a neutralizing roll as the neutralizing member, it is conceivable to use a neutralizing roll to which an AC bias voltage is applied.
In this case, since the surface of the intermediate transfer member and the surface of the charge removal roll have irregularities, it is impossible to bring the entire surface of the intermediate transfer member that rotates into contact with the grounded charge removal roller. The intermediate transfer member portion that does not come into contact with the charge removal roll is difficult to be neutralized in a state where the volume resistivity of the intermediate transfer member is high. That is, when the volume resistivity of the intermediate transfer member is high, there is a problem that it is difficult to reliably discharge the entire surface of the intermediate transfer member in a short time during which the intermediate transfer member passes through the discharging member. When the neutralization unevenness occurs on the surface of the intermediate transfer body, there is a problem that density unevenness corresponding to the neutralization unevenness occurs in the toner image that is primarily transferred to the surface of the intermediate transfer body during the next image formation.
There is also a problem that an expensive high-voltage power supply for static elimination is required because of the static elimination process by discharge.
Further, in the static elimination using the corotron, a large amount of ozone is generated, an image quality defect is generated due to the static elimination unevenness due to the adhesion of the adhering matter to the corotron, an intermediate between discharge products such as NOx, O ₃ and other ozone reaction products. There are problems such as adhesion to the transfer body.

As described above, in the case of using an intermediate transfer body having a high resistivity that exceeds 10 ¹⁴ Ωcm, a neutralizing member that performs neutralization after the completion of the secondary transfer is required. In particular, the value of the volume resistivity ρv The higher the value, the more difficult it is to uniformly remove the entire surface of the intermediate transfer member even if the charge eliminating member is used. Accordingly, considering only the transfer action, it is advantageous that the intermediate transfer member has a higher volume resistivity. However, the intermediate transfer member having a high resistivity requires a discharging step and it is difficult to remove the charge uniformly. Therefore, conventionally, an image forming apparatus using an intermediate transfer body having a high resistivity with a volume resistivity ρv of ρv> 10 ¹⁴ Ω has not been put into practical use.

Further, the following techniques (1) to (3) are known as those using an intermediate transfer body whose volume resistivity decreases when a physical stimulus is applied in a conventional image forming apparatus (for example, Patent Document 11). ~ 13).
In (1) to (3), the reason for using an intermediate transfer body having a reduced resistance value is that in (1), the intermediate transfer body that has been primarily transferred by a special method is neutralized before secondary transfer. This is because in (2) and (3), secondary transfer is performed by utilizing the decrease in the resistance value of the intermediate transfer member. That is, each of (1) to (3) is an image forming apparatus using an intermediate transfer body whose resistance value is lowered to perform special transfer, and an image forming apparatus that performs transfer by a normal transfer electric field. Is a completely different technology. In addition, (1) to (3) are all idea technologies and are not put into practical use. Moreover, there are problems as described below.

(1) Technology described in Patent Document 11 Here, FIGS. 7 and 8 are explanatory diagrams of the technology described in Japanese Patent Laid-Open No. 7-146616, which is Patent Document 11. FIG. In FIG. 7, Q1 represents a primary transfer region, Q2 represents a secondary transfer region, and 01a and 01b (see FIG. 7B) are blankets (intermediate transfer members) 01 (see FIG. 7A), respectively. The conductive rubber layer 01a mixed with carbon and the silicon rubber layer 01b mixed with a charge generating agent are shown. In FIG. 7C, a blanket 01 having photoconductivity is used as an intermediate transfer member, and the surface of the blanket 01 is charged to a polarity (+) opposite to the charging polarity (−) of the toner. In FIG. 7D, the toner is primarily transferred from the photosensitive drum 02 to the blanket 01 by the electrostatic force due to the charged charges. In FIG. 7E, after the primary transfer and before the secondary transfer, the light L is applied to the blanket 01 and the primary transfer toner image on the surface thereof to neutralize the charge (see FIG. 8A). In FIG. 7F, since the bonding force between the surface of the blanket 01 and the toner is weakened by static elimination, secondary transfer can be easily performed by light irradiation.
However, in this method, as shown in FIG. 8B, the surface of the intermediate transfer blanket 01 is charged with the toner charging polarity on the photosensitive drum 02 as a stage before the primary transfer from the photosensitive drum 02 to the blanket 01 is performed. Therefore, toner transfer occurs in the area before the primary transfer, and image quality deterioration due to image disturbance or blurring cannot be prevented.

Next, problems that occur when applied to an apparatus that multiplex-transfers a color image using a plurality of colors of toner will be described. In FIG. 8C, after the primary transfer of the first color toner to the intermediate transfer body blanket 01, the first color toner on the blanket 01 is prepared for the primary transfer of the second color toner. The toner is charged to a polarity opposite to the toner charging polarity above, and the toner on the photosensitive drum 02 is transferred to the blanket 01. At this time, since a transfer electric field sufficient to transfer the toner on the photosensitive drum 02 is applied between the photosensitive drum 02 and the blanket 01, the second color toner on the photosensitive drum 02 is transferred to the blanket 01. To do. On the other hand, the toner of the first color having the opposite polarity on the blanket 01 is transferred to the photosensitive drum 02 (see FIG. 8D).
Therefore, when the intermediate transfer member (blanket 01) described in (1) is applied to an apparatus for multiple transfer of color images, it is very difficult to obtain a color image with good image quality using multiple transfer. .

(2) Technology described in Patent Document 12 FIG. 9 is an explanatory diagram of the technology described in Japanese Patent Laid-Open No. 5-257398 which is Patent Document 12. In this publication, as shown in FIGS. 9A and 9B, the purpose is to prevent transfer in the pre-transfer area, and as shown in FIG. 9C, before the primary transfer. A precharge having the same polarity as the toner charging polarity is applied to the surface of the blanket 01 by the pre-transfer charger 03, and light is irradiated from the back surface of the intermediate transfer body 01 in the primary transfer region Q1, as shown in FIG. 9D. A method of primary transfer has been proposed.
Although this method can reduce the transfer in the pre-transfer area, only a single color image can be obtained, and it is difficult to obtain a clear full-color image.

FIG. 10 is an explanatory diagram of problems that occur when the developed image of the second color is transferred by the technique described in Japanese Patent Application Laid-Open No. 5-257398 which is Patent Document 12. In FIG. 10, a precharge is applied to the first color toner image already transferred onto the intermediate transfer body 01 (see FIG. 10A), and transfer is performed by irradiating light from the back surface in the primary transfer region Q1. At this time, the charge of the intermediate transfer body 01 is removed, but the toner charge of the first color is not removed.
As a result, there is a problem that the toner of the second color is scattered and uneven due to the electric field due to the toner charge that is not neutralized for the first color.

(3) Technology described in Patent Document 13 Here, FIG. 11 shows transfer by light irradiation using an intermediate transfer body whose resistance value is reduced by light irradiation described in JP-A-6-282181, which is Patent Document 13. It is explanatory drawing of the technique to perform. FIG. 12 is an explanatory diagram of a technique for performing transfer by applying a pressurizing force using an intermediate transfer body whose resistance value is reduced by a pressurizing force described in Japanese Patent Application Laid-Open No. Hei 6-282181. In FIG. 11, a transfer material 04 such as paper is electrostatically held on the intermediate transfer body 01, irradiated with light from the back surface of the intermediate transfer body 01 in the transfer region Q1, and a transfer electric field due to holes generated in the charge generation layer 01c. Has been proposed to transfer the toner image on the photoconductive drum 02 by applying the toner. In this method, since the transfer electric field is applied by reducing the resistance of the intermediate transfer body 01 by the action of light or the like in the transfer region Q1, the axial direction of the photosensitive drum 02 (perpendicular to the paper traveling direction). It has a low resistance. For this reason, there is a problem that it is difficult to prevent scattering and blurring of the toner image in the axial direction. FIG. 12 shows a technique for performing transfer by reducing the resistance by applying pressure by a roll instead of the light irradiation of FIG. 11, but the technique shown in FIG. 12 has the same problems as the technique shown in FIG. . Further, it is difficult to apply a uniform pressure to the intermediate transfer member due to the bending of the shaft of the intermediate transfer member support roll, surface irregularities, and the like, and there is a problem that transfer unevenness due to pressure distribution unevenness occurs.

As described above, the conventional intermediate transfer member has various problems, and a technique capable of solving these problems is desired.
JP-A-62-206567 JP-A-6-095521 Japanese Patent Laid-Open No. 5-200904 JP-A-6-228335 Japanese Patent Laid-Open No. 6-149081 Japanese Patent Laid-Open No. 6-149083 Japanese Patent Laid-Open No. 6-149079 JP-A-5-77252 Japanese Patent Laid-Open No. 10-63115 Japanese Unexamined Patent Publication No. Hei 8-248879 JP-A-7-146616 JP-A-5-257398 JP-A-6-282181

Therefore, the present invention aims to solve the conventional problems and achieve the following object.
That is, according to the present invention, when primary transfer and secondary transfer are performed using a transfer electric field, toner scattering can be suppressed in a state where the volume resistivity of the intermediate transfer member is high, and the transfer electric field is generated. An object of the present invention is to provide an intermediate transfer member that can easily remove the charge of the intermediate transfer member.
In addition, the present invention includes such an intermediate transfer member and a charge eliminating unit that removes the charged charge of the intermediate transfer member, so that an image quality defect due to toner scattering (blur), which is difficult with a conventional intermediate transfer member. Another object of the present invention is to provide an image forming apparatus capable of stably obtaining high-quality transfer image quality.

In order to solve the above problems, the present inventors have found the following present invention in order to achieve the above problems.
That is, the present invention
<1> An intermediate transfer body having a base material and a surface layer provided on the base material,
The intermediate transfer member is characterized in that the surface layer is a photoconductive layer.

<2> The intermediate transfer member according to <1>, wherein the photoconductive layer contains a charge transport material, a charge generation material, and a binder resin.

<3> An intermediate transfer body having a base material and a surface layer provided on the base material,
The intermediate transfer member, wherein the surface layer is a charge transport layer and a photoconductive layer provided on the substrate side of the charge transport layer.

<4> The intermediate transfer according to any one of <1> to <3>, wherein the base material is composed of a thermosetting resin or a thermoplastic resin and has a Young's modulus of 1,000 Mpa or more. Is the body.

<5> The intermediate transfer member according to any one of <1> to <4>, wherein the base material has a volume resistivity of 1 × 10 ⁶ to 1 × 10 ¹³ Ωcm.

<6> The intermediate transfer member according to <5>, wherein the base material is composed of a polyimide resin obtained by dispersing a conductive agent.

<7> The intermediate transfer member according to any one of <1> to <6>, wherein the surface layer contains fluorine-based resin particles.

<8> After transferring the intermediate transfer member according to any one of <1> to <7> and the toner image formed on the surface of the intermediate transfer member to a transfer material, the surface of the intermediate transfer member is irradiated with light. An image forming apparatus comprising: a light discharging unit that discharges by irradiation.

<9> The image forming apparatus according to <8>, wherein a spherical toner having a shape factor (SF) defined by the following formula (1) of the toner of 140 to 100 is used.
Formula (1)
(SF) = [(absolute maximum length of toner particles) ² × π × 100] / [(projection area of toner particles) × 4]

According to the present invention, when primary transfer and secondary transfer are performed using a transfer electric field, toner scattering can be suppressed in a state where the volume resistivity of the intermediate transfer member is high, and the transfer electric field is generated. It is possible to provide an intermediate transfer member that can easily remove the charge of the intermediate transfer member.
In addition, by providing such an intermediate transfer member and a charge removing unit that removes the charged charge of the intermediate transfer member, image quality defects due to toner scattering (blur) are extremely small, and high-quality transfer image quality can be stably obtained. It is possible to provide an image forming apparatus capable of performing the above.

Hereinafter, an intermediate transfer member of the present invention and an image forming apparatus including the same will be described in detail.
<Intermediate transfer member>
The intermediate transfer member of the present invention is an intermediate transfer member having a base material and a surface layer provided on the base material, wherein the surface layer is a photoconductive layer.
Another intermediate transfer member of the present invention is an intermediate transfer member having a base material and a surface layer provided on the base material, wherein the surface layer is a charge transport layer and the charge transport material It is a photoconductive layer having a charge generation layer provided on the substrate side of the layer.
The intermediate transfer member of the present invention can be configured in a drum shape or a belt shape.
Hereinafter, each member constituting the intermediate transfer member of the present invention will be described.

[Surface layer]
In the intermediate transfer member of the present invention, the surface layer is (1) a photoconductive layer, or (2) a photoconductive layer having a charge transport layer and a charge generation layer provided on the substrate side of the charge transport layer. It is characterized by being.
Here, any of the photoconductive layers in the present invention is a dielectric when it is not irradiated with light, has a high volume resistivity, and exhibits conductivity when irradiated with light.
As described above, since the surface layers in the present invention are all photoconductive layers, they have a volume resistivity of a dielectric when not irradiated with light and exhibit conductivity when irradiated with light. Thus, the resistivity is changed.

The intermediate transfer member having such a surface layer is subjected to light non-irradiation in the primary transfer and the secondary transfer. At this time, the intermediate transfer member has a high volume resistivity equivalent to that of a dielectric. For this reason, when an intermediate transfer body having such a high volume resistivity is used and a transfer voltage is applied, the transfer electric field does not spread and toner scattering can be suppressed, and a good transfer image can be obtained. it can.
Here, “the volume resistivity is high (high)” in the present invention means that the volume resistivity in a state where light is not irradiated to the photoconductive layer as the surface layer is 1 × 10 ^13.5 Ωcm or more. The volume resistivity is preferably 1 × 10 ¹⁴ Ωcm or more.

The photoconductive layer (1) is a dielectric that has a high volume resistivity in the state where light is not irradiated, and needs only to exhibit conductivity when irradiated with light. The material constituting the surface layer may be a material obtained by adding a photoconductive substance, or may be a photosensitive layer used in an electrophotographic photoreceptor. Further, as shown in (2), it may be a photoconductive layer having a multilayer structure composed of a charge transport layer and a charge generation layer.
Hereinafter, the aspect of the surface layer in this invention is demonstrated.

Of the photoconductive layers of (1) above, those having a single layer structure are preferably layers containing a charge transport material, a charge generation material, and a binder resin.
As described above, the intermediate transfer member having a surface layer which is a photoconductive layer having a single layer structure is provided with a photoconductive layer (surface layer) 121 having a single layer structure on a substrate 110 as shown in FIG. If it is the structure which has, it may contain arbitrary layers, for example, an undercoat layer and a surface protective layer, as needed. Here, FIG. 1 is a schematic cross-sectional view showing a configuration example of the intermediate transfer member of the present invention.
Hereinafter, each component constituting the photoconductive layer having such a single layer structure will be described in order.

(Charge transport material)
In the present invention, the charge transport material constituting the photoconductive layer having a single layer structure is preferably a hydrazone compound represented by the following general formula (I) (hereinafter referred to as “specific hydrazone compound” as appropriate). It is mentioned as a thing.

In the general formula (I), R ^{1 to} R ⁴ each independently represents an alkyl group or an aryl group.
Examples of the alkyl group represented by R ^{1 to} R ⁴ include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, and a hexyl group. Is a methyl group.
Examples of the aryl group represented by R ^{1 to} R ⁴ include a phenyl group, a naphthyl group, a tolyl group, a xylyl group, a biphenyl group, an anthryl group, a phenanthryl group, and a pyrenyl group. Among these, a phenyl group is preferable. Group, a naphthyl group.

Specific examples of the hydrazone compound represented by the above general formula (I) include compounds in which R ^{1 to} R ⁴ have the following substituents in general formula (I), but are not limited thereto. is not.
1. Compound 1: R ¹ = methyl group, R ² = phenyl group, R ³ = methyl group, R ⁴ = phenyl group Compound 2: R ¹ = methyl group, R ^{2 to} R ⁴ = phenyl group Compound 3: R ^{1 to} R ⁴ = phenyl group Compound 4: R ¹ = methyl group, R ² = naphthyl group, R ³ = methyl group, R ⁴ = phenyl group Compound 5: R ¹ = methyl group, R ² = naphthyl group, R ³ , R ⁴ = phenyl group Compound 6: R ¹ = phenyl group, R ² = naphthyl group, R ³ , R ⁴ = phenyl group Compound 7: R ¹ = phenyl group, R ² = naphthyl group, R ³ = phenyl group, R ⁴ = naphthyl group Compound 8: R ^{1 to} R ⁴ = naphthyl group9. Compound 9: R ¹ = phenyl group, R ² = phenanthryl group, R ³ , R ⁴ = phenyl group10. Compound 10: R ¹ = phenyl group, R ² = pyrenyl group, R ³ , R ⁴ = phenyl group In the above compound, when the substituent is a naphthyl group or a phenanthryl group, the substitution position is a naphthyl group Then, the α-position, the β-position, and the phenanthryl group may be any of the 1-position to the 10-position.

  The charge polarity of the photoconductive layer changes depending on the charge transport polarity of the charge transport material. The photoconductive layer using the specific hydrazone compound as the charge transport material is a dielectric layer having a high volume resistivity when not irradiated with light, and has positive hole carriers when irradiated with light. Can transport charges.

  In addition, as the charge transport material constituting the photoconductive layer having a single layer structure, the specific hydrazone compound may be used alone or in combination of two or more, or the specific hydrazone compound and other conventionally known compounds may be used. A charge transport material may be used in combination. Moreover, you may use only a conventionally well-known charge transport material individually or in mixture of 2 or more types.

  Conventionally known charge transport materials include oxadiazole derivatives such as 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole, 1,3,5-triphenylpyrazoline, 1- [Pyridyl- (2)]-3- (p-diethylaminostyryl) -5- (p-diethylaminostyryl) pyrazoline and other pyrazoline derivatives, triphenylamine, tri (p-methylphenyl) amine, N, N-bis ( Aromatic tertiary amino compounds such as 3,4-dimethylphenyl) biphenyl-4-amine, dibenzylaniline, 9,9-dimethyl-N, N-di (p-tolyl) fluorenon-2-amine, N, Aromatic tertiary diamino such as N′-diphenyl-N, N′-bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine Compound, 1,2,4-triazine derivatives such as 3- (4′dimethylaminophenyl) -5,6-di- (4′-methoxyphenyl) -1,2,4-triazine, 4-diethylaminobenzaldehyde 1,1-diphenylhydrazone, 4-diphenylaminobenzaldehyde-1,1-diphenylhydrazone, [p- (diethylamino) phenyl] (1-naphthyl) phenylhydrazone, 1-pyrenediphenylhydrazone, 9-ethyl-3-[( 2-methyl-1-indolinylimino) methyl] carbazole,-(2-methyl-1-indolinyliminomethyl) triphenylamine, 9-methyl-3-carbazole diphenylhydrazone, 1,1′-di (4,4 '-Methoxyphenyl) acrylaldehyde diphenylhydrazone, β, β-bis (me Hydrazone derivatives such as xylphenyl) vinyldiphenylhydrazone, quinazoline derivatives such as 2-phenyl-4-styryl-quinazoline, benzofuran derivatives such as 6-hydroxy-2,3-di- (p-methoxyphenyl) -benzofuran, p- ( Hole transport materials such as α-stilbene derivatives such as 2,2-diphenylvinyl) -N, N-diphenylaniline, enamine derivatives, carbazole derivatives such as N-ethylcarbazole, poly-N-vinylcarbazole and derivatives thereof. It is done.

  Further, conventionally known charge transport materials include quinone compounds such as chloranil, bromoanil and anthraquinone, tetracyanoquinodimethane compounds, 2,4,7-trinitrofluorenone, 2,4,5,7-tetranitro- Fluorenone compounds such as 9-fluorenone and di (3,4-dimethylphenyl) (4-phenylphenyl) amine, 2- (4-biphenyl) -5- (4-t-butylphenyl) -1,3,4- Oxadiazoles such as oxadiazole, 2,5-bis (4-naphthyl) -1,3,4-oxadiazole, 2,5-bis (4-diethylaminophenyl) 1,3,4 oxadiazole Compound, xanthone compound, thiophene compound, 3,3 ′, 5,5′tetra-t-butyldiphenoquinone, 3,5-dimethyl-3 ′, 5′- Electron transporting materials such as diphenoquinone compounds such -t- butyl-4,4'-diphenoquinone also included. Moreover, the polymer etc. which have the group which consists of a compound shown above in the principal chain or a side chain can be used.

In the photoconductive layer having a single-layer structure in the present invention, these charge transport materials are preferably contained in an amount of 40 to 200 parts by mass, and 50 to 150 parts by mass with respect to 100 parts by mass of the binder resin. More preferred.
In addition, when using together the said specific hydrazone type compound and a conventionally well-known hydrazone type compound, it is preferable that specific hydrazone type compound contains 50 mass% or more with respect to the total amount of charge transport material, and contains 70 mass% or more. More preferably.

(Charge generation material)
In the present invention, the charge generation material constituting the photoconductive layer having a single layer structure includes amorphous selenium, crystalline selenium, selenium-tellurium alloy, selenium-arsenic alloy, other selenium compounds and selenium alloys, zinc oxide, Inorganic photoconductors such as titanium oxide and dye-sensitized ones, various phthalocyanine pigments such as metal-free phthalocyanine, titanyl phthalocyanine, copper phthalocyanine, tin phthalocyanine, gallium phthalocyanine, squalium, anthanthrone, perylene, Various organic pigments and dyes such as azo, anthraquinone, pyrene, pyrylium salt and thiapyrylium salt are used. In addition, these organic pigments generally have several types of crystals. In particular, phthalocyanine pigments have various crystal types including α type and β type. Any of these crystal forms can be used as long as it is a pigment capable of obtaining the above characteristics.

In the present invention, the following compounds are particularly suitable as charge generation materials that can provide excellent performance. That is, in the Bragg angle (2θ ± 0.2 °) of the X-ray diffraction spectrum using Cukα rays, diffraction peaks are at least at positions of 7.6 °, 10.0 °, 25.2 °, 28.0 °. At least 7.3 °, 16.5 °, 25.4 ° in the Bragg angle (2θ ± 0.2 °) of the X-ray diffraction spectrum using hydroxygallium phthalocyanine typified by a crystal form having Ckα rays , At least 9.5 ° in a Bragg angle (2θ ± 0.2 °) of an X-ray diffraction spectrum using a chlorogallium phthalocyanine represented by a crystal type having a diffraction peak at a position of 28.1 ° and a Cukα ray. , 24.2 °, 27.3 °, titanyl phthalocyanine typified by a crystal form having a diffraction peak.
Note that the position of these peak intensities may slightly deviate from these values depending on the shape of the crystal and the measurement method, but if the X-ray diffraction patterns are basically the same, they are the same crystal type. Can judge.
These charge generating materials can be used alone or in combination of two or more.

  In the photoconductive layer having a single layer structure in the present invention, these charge generation materials are preferably contained in an amount of 2 to 20 parts by mass, and preferably 5 to 15 parts by mass with respect to 100 parts by mass of the binder resin. More preferred.

(Binder resin)
In the present invention, any binder resin can be used for the photoconductive layer having a single-layer structure, and in particular, a resin having compatibility with the charge transport material and appropriate strength is desirable. .
Specifically, the following can be exemplified. For example, polycarbonate resin such as bisphenol A type or bisphenol Z type and its copolymer, polyarylate resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer Resin, vinylidene chloride-acrylonitrile copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly-N-vinylcarbazole, etc. .
The molecular weight of such a binder resin is appropriately selected depending on the film forming conditions such as the film thickness of the photoconductive layer and the solvent, but is usually 3000 to 300,000 in terms of viscosity average molecular weight, more preferably 20,000 to 200,000. The range of is appropriate.
These binder resins can be used alone or in combination of two or more.

(Other ingredients)
In the present invention, the photoconductive layer having a single-layer structure includes an antioxidant, a light stabilizer, and a heat stabilizer for the purpose of preventing deterioration caused by ozone, oxidizing gas, or light / heat generated in the electrophotographic apparatus. Additives such as agents can be added.
For example, examples of the antioxidant include hindered phenol, hindered amine, paraphenylenediamine, arylalkane, hydroquinone, spirochroman, spiroidanone and derivatives thereof, organic sulfur compounds, and organic phosphorus compounds.

Here, specific compound examples of the antioxidant are shown below.
Examples of phenolic antioxidants include 2,6-di-t-butyl-4-methylphenol, styrenated phenol, and n-octadecyl-3- (3 ′, 5′-di-t-butyl-4′-hydroxy. Phenyl) -propionate, 2,2′-methylene-bis- (4-methyl-6-tert-butylphenol), 2-t-butyl-6- (3′-tert-butyl-5′-methyl-2′-) Hydroxybenzyl) -4-methylphenyl acrylate, 4,4'-butylidene-bis- (3-methyl-6-tert-butyl-phenol), 4,4'-thio-bis- (3-methyl-6-t -Butylphenol), 1,3,5-tris (4-t-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, tetrakis- [methylene-3- (3 ', 5'-di-t- Butyl-4'-hydroxy -Phenyl) propionate] -methane, 3,9-bis [2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl] -2,4 , 8,10-tetraoxaspiro [5,5] undecane, 3-3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) stearyl propionate, and the like.

  Examples of hindered amine compounds include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, 1- [2- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] ethyl] -4- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy]- 2,2,6,6-tetramethylpiperidine, 8-benzyl-7,7,9,9-tetramethyl-3-octyl-1,3,8-triazaspiro [4,5] undecane-2,4-dione 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, dimethyl-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine succinate Polycondensate, poly [{6- (1,1,3,3-tetramethylbutyl) imino-1,3,5-triazine-2,4-diimyl} {(2,2,6,6-tetra Methyl-4-piperidyl) imino} hexamethylene {(2,3,6,6-tetramethyl-4-piperidyl) imino}], 2- (3,5-di-t-butyl-4-hydroxybenzyl)- 2-n-butylmalonate bis (1,2,2,6,6-pentamethyl-4-piperidyl), N, N′-bis (3-aminopropyl) ethylenediamine-2,4-bis [N-butyl- N- (1,2,2,6,6, -pentamethyl-4piperidyl) amino] -6-chloro-1,3,5-triazine condensate and the like.

Examples of organic sulfur antioxidants include dilauryl-3,3′-thiodipropionate, dimyristyl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, pentaerythritol-tetrakis. -(Β-lauryl-thiopropionate), ditridecyl-3,3′-thiodipropionate, 2-mercaptobenzimidazole and the like.
Examples of the organophosphorus antioxidant include trisnonylphenyl phosfte, triphenyl phosfte, tris (2,4-di-t-butylphenyl) -phosfte and the like.
Organic sulfur-based and organic phosphorus-based antioxidants are referred to as secondary antioxidants, and can provide a synergistic effect when used in combination with phenolic or amine-based primary antioxidants.
These antioxidants are preferably added in the range of 0.1 to 3.0% by mass in the total solid content of the photoconductive layer having a single layer structure, and 0.2 to 2.0% by mass. More preferably, it is added in a range.

Examples of the light stabilizer include benzophenone, benzotriazole, dithiocarbamate, and tetramethylpiperidine derivatives.
Here, specific compound examples of the light stabilizer are shown below.
Examples of the benzophenone light stabilizer include 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, and 2,2′-di-hydroxy-4-methoxybenzophenone.
Examples of the benzotriazole-based light stabilizer include 2-(-2′-hydroxy-5′-methylphenyl) -benzotriazole, 2- [2′-hydroxy-3 ′-(3 ″, 4 ″, 5 ″, 6 "-tetra-hydrophthalimido-methyl) -5'-methylphenyl] -benzotriazole, 2-(-2'-hydroxy-3'-t-butyl-5'-methylphenyl-)-5-chlorobenzotriazole 2- (2′-hydroxy-3′-t-butyl-5′-methylphenyl-)-5-chlorobenzotriazole, 2- (2′-hydroxy-3 ′, 5′-t-butylphenyl-) -Benzotriazole, 2- (2'-hydroxy-5'-t-octylphenyl) -benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-t-amylphenyl) -benzotriazole and the like Cited It is.
Other compounds include 2,4, di-t-butylphenyl-3 ′, 5′-di-t-butyl-4′-hydroxybenzoate, nickel dibutyl-dithiocarbamate, and the like.
These light stabilizers are preferably added in the range of 0.1 to 3.0% by mass in the total solid content of the photoconductive layer having a single layer structure, and 0.2 to 2.0% by mass. More preferably, it is added in a range.

In addition, when the photoconductive layer having a single layer structure is the outermost surface layer, a releasable solid particle (fluorine-based resin particle) made of a fluorine-based resin such as Teflon (registered trademark) is used to improve the surface lubricity. ) Can also be contained.
Below, the structural example of the photoconductive layer of a single layer structure at the time of adding a fluorine-type resin particle is shown.
Examples of the fluorine-based resin particles include tetrafluoroethylene resin, trifluorinated ethylene resin, hexafluoropropylene resin, vinyl fluoride resin, vinylidene fluoride resin, difluorodiethylene chloride resin, and copolymers thereof. It is desirable to appropriately select one or two or more types from among them, and particularly preferred are tetrafluoroethylene resin and vinylidene fluoride resin.
The content of the fluororesin particles in the single-layer photoconductive layer is suitably from 0.1 to 40% by weight, particularly preferably from 1 to 30% by weight, based on the total layer. If the content is less than 1% by mass, the modification effect due to the dispersion of the fluororesin particles is not sufficient. On the other hand, if the content exceeds 40% by mass, the light transmission property decreases, and the residual potential increases due to repeated use. .
The primary particle diameter of the fluororesin particles is preferably 0.05 to 1 μm, more preferably 0.1 to 0.5 μm. When the primary particle diameter is less than 0.05 μm, aggregation during dispersion tends to proceed. On the other hand, if it exceeds 1 μm, image quality defects are likely to occur.

In addition to the fluorine resin particles, inorganic particles may be further added to the photoconductive layer having a single layer structure.
The content of the inorganic particles in the photoconductive layer having a single layer structure is suitably 0.1 to 30% by mass, particularly preferably 1 to 20% by mass, based on the total amount of the layer. If the content is less than 1% by mass, the modification effect due to the dispersion of inorganic particles is not sufficient. On the other hand, if the content exceeds 30% by mass, the residual potential increases due to repeated use.
Examples of inorganic particles include alumina, silica (silicon dioxide), titanium oxide, zinc oxide, cerium oxide, zinc sulfide, magnesium oxide, copper sulfate, sodium carbonate, magnesium sulfate, potassium chloride, calcium chloride, sodium chloride, nickel sulfate. , Antimony, manganese dioxide, chromium oxide, tin oxide, zirconium oxide, barium sulfate, aluminum sulfate, silicon carbide, titanium carbide, boron carbide, tungsten carbide, zirconium carbide, one of these, or two if necessary The above is used, but silica is preferably used. The silica particles are preferably produced by a chemical flame CVD method. As a specific example, silica particles are obtained by subjecting chlorosilane gas to a gas phase reaction in a high-temperature flame of oxygen-hydrogen mixed gas or hydrocarbon-oxygen mixed gas. Is preferred.

  In addition, as the inorganic particles, particles having a hydrophobic surface are preferable. As the hydrophobizing agent, for example, a siloxane compound, a silane coupling agent, a titanium coupling agent, a polymer fatty acid or a metal salt thereof is used. Examples of the siloxane compound include polydimethylsiloxane, dihydroxypolysiloxane, octamethylcyclotetrasiloxane, and examples of the silane coupling agent include γ- (2-aminoethyl) aminopropyltrimethoxysilane and γ- (2-aminoethyl). Aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β- (N-vinylbenzylaminoethyl) γ-aminopropyltrimethoxysilane hydrochloride, hexamethyldisilazane, methyltrimethoxysilane, butyltrimethoxy Silane, isobutyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, dodecyltrimethoxysilane, phenyltrimethoxysilane, o-methylphenyltrime Toxisilane, p-methylphenyltrimethoxysilane and the like can be mentioned.

  The primary particle diameter of the inorganic particles is preferably 0.005 to 2.0 μm, more preferably 0.01 to 1.0 μm. If the primary particle diameter of the inorganic fine particles is less than 0.005 μm, sufficient mechanical strength on the surface of the intermediate transfer member cannot be obtained, and aggregation during dispersion tends to proceed. On the other hand, if it exceeds 2 μm, the roughness of the surface of the intermediate transfer member becomes large. When a cloning blade is used as a cleaning device, the cleaning blade is worn and damaged, and the cleaning characteristics are deteriorated. It tends to occur.

In order to disperse the fluorine resin particles and further inorganic particles in the single layer photoconductive layer, media dispersers such as a ball mill, vibrating ball mill, attritor, sand mill, horizontal sand mill, stirring, ultrasonic dispersion Medialess dispersers such as a mill, a roll mill, and a high-pressure homogenizer can be used. Furthermore, examples of the high-pressure homogenizer include a collision method in which the dispersion liquid is dispersed by liquid-liquid collision or liquid-wall collision in a high pressure state, and a penetration method in which the fine liquid is penetrated and dispersed in a high pressure state.
Examples of the dispersion of the coating liquid for forming a single-layer photoconductive layer in which such releasable solid particles are dispersed include fluorine resin particles in a solution of a binder resin or a charge transport material dissolved in a solvent. And a method of dispersing inorganic particles.

Furthermore, in the present invention, when forming a photoconductive layer having a single layer structure, a dispersion aid is used to improve the dispersion stability of each dispersion in the dispersion and to prevent agglomeration during coating formation. It is also effective to add a small amount of an agent.
Examples of the dispersion aid include fluorine-based surfactants, fluorine-based polymers, silicone-based polymers, and silicone oils. Among them, fluorine-based polymers, in particular, fluorine-based comb-type graft polymers are effective as a dispersion aid, and examples of fluorine-based comb-type graft polymers include macromonomers composed of acrylic ester compounds, methacrylic ester compounds, styrene compounds, and the like. A resin graft-polymerized from perfluoroalkylethyl methacrylate is preferred.

(Formation of single-layer photoconductive layer)
In the present invention, the photoconductive layer having a single layer structure is formed by preparing a coating solution containing each of the above-described components and applying the coating solution on a desired substrate.
Solvents used in preparing the coating solution include, for example, aromatic hydrocarbons such as benzene, toluene and chlorobenzene, ketones such as acetone and 2-butanone, and halogenations such as methylene chloride, chloroform and ethylene chloride. Aliphatic hydrocarbons, cyclic or linear ethers such as tetrahydrofuran, dioxane, ethylene glycol and diethyl ether, or a mixed solvent thereof can be used.
In addition, as a method of dispersing the charge generating material in the binder resin, as a method of dispersing the charge generating material in the binder resin, a roll mill, a ball mill, a vibrating ball mill, an attritor, a dyno mill, a sand mill, a colloid mill, or the like Can be used.

  As a coating method of the coating solution, a coating method such as a dip coating method, a ring coating method, a spray coating method, a bead coating method, a blade coating method, a roller coating method, a knife coating method, or a curtain coating method can be used. . Moreover, it is preferable to dry by heating after drying by touching at room temperature. The heat drying is desirably performed at a temperature in the range of 30 ° C. to 200 ° C. for a time in the range of 5 minutes to 2 hours.

  The thickness of the photoconductive layer having a single-layer structure thus obtained is preferably in the range of 10 to 200 μm, more preferably in the range of 15 to 100 μm, from the viewpoint of developing the function as the photoconductive layer. It is a range.

Next, the photoconductive layer having the charge transport layer and the charge generation layer provided on the substrate side of the charge transport layer (2) will be described in detail.
If an intermediate transfer member having a surface layer that is a photoconductive layer having such a multilayer structure is an indispensable configuration in which a charge generation layer and a charge transport layer are provided in this order on a base material, the intermediate transfer member is necessary. An arbitrary layer, for example, an undercoat layer or a surface protective layer may be included.
Hereinafter, the intermediate transfer member provided with the multilayered photoconductive layer will be described in order with reference to FIG.

Here, FIG. 2 is a schematic cross-sectional view showing an example of the configuration of the intermediate transfer member of the present invention, (A) is a schematic cross-sectional view showing the configuration of the intermediate transfer member 100a of the present invention, and (B) is the main transfer unit. It is a schematic sectional drawing which shows the structure of the intermediate transfer body 100b of invention.
As shown in FIG. 2A, the structure of the intermediate transfer member 100a of the present invention includes a substrate 110, a surface layer 120 including an undercoat layer 122, a charge generation layer 124, and a charge transport layer 126. including.
As shown in FIG. 2B, the structure of the intermediate transfer body 100b of the present invention includes a substrate 110, an undercoat layer 122, a charge generation layer 124, a charge transport layer 126, and a surface protective layer 128. And a surface layer 120 made of
In such intermediate transfer bodies 100a and 100b, the charge generation layer 124 and the charge transport layer 126 constitute a photoconductive layer.

(Charge generation layer)
The charge generation layer is a layer provided between the base material and the charge transport layer and has a function of generating charges in a state where light is irradiated. Such a charge generation layer is formed by forming a charge generation material by vacuum vapor deposition or by dispersing and applying the charge generation material together with an organic solvent and a binder resin.

As the charge generation material used for the charge generation layer, the same material as the charge generation material constituting the photoconductive layer having the single layer structure is used. These charge generation materials can be used alone or in combination of two or more.
Further, as the binder resin used in the charge generation layer, the same resin as the charge generation material constituting the photoconductive layer having the single layer structure is used. Moreover, these binder resins can be used alone or in combination of two or more.

The blending ratio (mass ratio) between the charge generating substance and the binder resin is preferably in the range of 10: 1 to 1:10.
As a method for dispersing the charge generating material in the binder resin, methods such as a roll mill, a ball mill, a vibrating ball mill, an attritor, a dyno mill, a sand mill, and a colloid mill can be used.
The thickness of the charge generation layer is generally set in the range of 0.01 to 5 μm, preferably 0.05 to 2.0 μm.

Note that the light absorption in the charge generation layer varies by changing the thickness of the charge generation layer, but the light absorption increases by increasing the thickness of the charge generation layer, and the film thickness in the entire photoconductive layer. Even if there is a distribution, variation in sensitivity to light can be reduced, and in-plane uniformity of transfer efficiency can be improved.
Note that the amount of reflected light of the charge generation layer is influenced not only by the film thickness but also by the absorption coefficient of the pigment with respect to the irradiation light, the blending ratio of the pigment and the binder resin, and the dispersion state of the pigment. It is not specified from the thickness.

(Charge transport layer)
The charge transport layer is a layer provided on the surface of the charge generation layer described above, and is a dielectric layer that has a high volume resistivity when not irradiated with light, and has a negative polarity electron or state when irradiated with light. It has a function of transporting charges by any carrier of positive holes. Such a charge transport layer is formed by dissolving a charge generation material and a binder resin in a suitable solvent and coating them.

  As the charge transport material used for the charge transport layer, the same charge transport materials as those constituting the single-layer photoconductive layer are used. These charge transport materials can be used alone or in combination of two or more.

  Since the charge polarity of the photoconductive layer varies depending on the charge transport polarity of the charge transport material, the charge polarity of the intermediate transfer member is determined by the charge transport polarity of the charge transport material. When a hole transport material is used, the intermediate transfer member is used with negative charge, and when an electron transport material is used, the intermediate transfer member is used with positive charge. Further, when both are mixed as a charge transport material, the intermediate transfer member has both charged polarities.

Any binder resin can be used for the charge transport layer, and it is particularly desirable that the binder resin is compatible with the charge transport material and has an appropriate strength.
Examples of binder resins include various polycarbonate resins and copolymers thereof such as bisphenol A, bisphenol Z, bisphenol C, and bisphenol TP; polyarylate resins and copolymers thereof; polyester resins, methacrylic resins, acrylic resins, poly Vinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer resin, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride copolymer resin, silicone resin Silicone alkyd resin, phenol-formaldehyde resin, styrene-acrylic copolymer resin, ethylene-alkyd resin, poly-N-vinylcarbazole resin, polyvinyl butyral resin, polyphenylene ether resin, etc. It is.
These binder resins can be used alone or as a mixture of two or more.
The molecular weight of the binder resin used in the present invention is appropriately selected depending on the film forming conditions such as the thickness of the charge transport layer and the solvent, but is usually 3000 to 300,000 in terms of viscosity average molecular weight, more preferably 20,000 to A range of 200,000 is appropriate.

The charge transport layer can be formed by applying and drying a solution in which the charge transport material and the binder resin shown above are dissolved in a suitable solvent.
Examples of the solvent used for forming the charge transport layer include aromatic hydrocarbons such as benzene, toluene and chlorobenzene; ketones such as acetone and 2-butanone; halogenation such as methylene chloride, chloroform and ethylene chloride. Aliphatic hydrocarbons; cyclic or linear ethers such as tetrahydrofuran, dioxane, ethylene glycol, diethyl ether; or a mixed solvent thereof can be used.
A small amount of silicone oil can be added to the coating solution as a leveling agent for improving the smoothness of the coating film.

Coating methods include dip coating, ring coating, spray coating, bead coating, blade coating, roller coating, knife coating, curtain coating, etc., depending on the shape and application of the intermediate transfer member. It can be done using the method. Moreover, it is preferable to dry by heating after drying by touching at room temperature. The heat drying is desirably performed at a temperature in the range of 30 ° C. to 200 ° C. for a time in the range of 5 minutes to 2 hours.
The compounding ratio of the charge transport material and the binder resin is preferably 10: 1 to 1: 5.
The thickness of the charge transport layer is generally 5 to 50 μm, preferably 10 to 40 μm.

Additives such as antioxidants, light stabilizers, heat stabilizers, etc. to the charge transport layer for the purpose of preventing degradation due to ozone, oxidizing gas, or light / heat generated in the electrophotographic apparatus. be able to. Specific compound examples of the antioxidant and the light stabilizer are the same as those of the charge transporting material constituting the single-layer photoconductive layer.
The antioxidant is preferably added in the range of 0.1 to 3.0% by mass in the total solid content of the charge transport layer, and is added in the range of 0.2 to 2.0% by mass. More preferably.
The light stabilizer is preferably added in the range of 0.1 to 3.0% by mass in the total solid content of the charge transport layer, and is added in the range of 0.2 to 2.0% by mass. More preferably.

The charge transport layer may contain at least one electron accepting substance for the purpose of improving sensitivity, reducing residual potential, reducing fatigue during repeated use, and the like.
Examples of the electron-accepting substance used in the charge transport layer in the present invention include succinic anhydride, maleic anhydride, dibromomaleic anhydride, phthalic anhydride, tetrabromophthalic anhydride, tetracyanoethylene, tetracyanoquinodimethane, Examples include o-dinitrobenzene, m-dinitrobenzene, chloranil, dinitroanthraquinone, trinitrofluorenone, picric acid, o-nitrobenzoic acid, p-nitrobenzoic acid, and phthalic acid. Of these, fluorenone-based, quinone-based, and benzene derivatives having electron-withdrawing substituents such as Cl, CN, NO ₂ are particularly preferable.
These electron-accepting substances are preferably added in the range of 3 to 30% by mass in the charge transport layer, and more preferably in the range of 5 to 20% by mass.

Furthermore, when the charge transport layer is the outermost surface layer, a releasable solid particle made of a fluororesin such as Teflon (registered trademark) may be included in the charge transport layer in order to improve surface lubricity. Is possible. Moreover, you may use together a fluorine-type resin particle and an inorganic particle.
Specific examples of the fluorine-based resin particles and inorganic particles, the primary particle diameter, the content in the layer, the dispersion method, and the like are the same as those of the releasable solid particles constituting the single-layered photoconductive layer.

(Undercoat layer)
The undercoat layer in the present invention is a layer provided between the substrate 110 and the charge generation layer 124 as shown in FIGS. 2A and 2B, and serves as an electrical blocking layer. And the role of improving the wettability with the charge generation layer which is the upper layer.
In the case of an intermediate transfer member provided with a single-layer structure photoconductive layer, the undercoat layer serves as an electrical blocking layer and improves the wettability between the upper single-layer structure photoconductive layer. And fulfill.
Such an undercoat layer is composed of acetal resin such as polyvinyl butyral, polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride. -Organic metals containing zirconium, titanium, aluminum, manganese, silicon atoms, etc. in addition to polymer resin compounds such as vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, melamine resin Formed from materials such as compounds. These compounds can be used alone or as a mixture or polycondensate of a plurality of compounds. Among them, an organometallic compound containing a zirconium atom or a silicon atom is excellent in performance such as a low residual potential, a small potential change due to the environment, and a small potential change due to repeated use. The organometallic compound can be used alone or in combination, or mixed with the above-described resin.

  Examples of organometallic compounds containing silicon atoms include, for example, vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ -Glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β -(Aminoethyl) -γ-aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, γ-chloropropyltrimethoxysilane, and the like. Among these, particularly preferably used silicon compounds are vinyltriethoxysilane, vinyltris (2-methoxyethoxysilane), 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, N-2- (aminoethyl) 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) 3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, Examples include silane coupling agents such as N-phenyl-3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-chloropropyltrimethoxysilane.

  Examples of organometallic compounds containing a zirconium atom include zirconium butoxide, zirconium zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl acetoacetate butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, Zirconium octanoate, zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide and the like.

  Examples of organometallic compounds containing titanium atoms include tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, Examples include titanium lactate ammonium salt, titanium lactate, titanium lactate ethyl ester, titanium triethanolamate, and polyhydroxytitanium stearate.

  Examples of the organometallic compound containing an aluminum atom include aluminum isopropylate, monobutoxy aluminum diisopropylate, aluminum butyrate, diethyl acetoacetate aluminum diisopropylate, aluminum tris (ethyl acetoacetate) and the like.

  In the case of the undercoat layer in the present invention, when the film thickness is too large, the electrical barrier becomes too strong, causing desensitization and an increase in potential due to repetition. Therefore, in the case of forming the undercoat layer having the above-described configuration, the film thickness range is set to 0.1 to 3 μm.

(Surface protective layer)
In the present invention, it is also possible to form a surface protective layer on the charge transport layer for the purpose of improving the wear resistance of the intermediate transfer member and extending its life or preventing chemical change of the charge transport layer. It is.
Also, in the case of an intermediate transfer member having a single-layer photoconductive layer, the wear resistance of the intermediate transfer member is improved and the life is extended, or chemical change of the single-layer photoconductive layer is prevented. For this purpose, a surface protective layer can be formed on the photoconductive layer.
Examples of the surface protective layer include an insulating surface protective layer made of an insulating resin, a resistance control type surface protective layer in which a resistance control agent such as a metal oxide is dispersed, and charge transport by a polymer compound imparted with charge transportability. For example, a protective surface protective layer.

  As the insulating resin used for the insulating surface protective layer made of an insulating resin, a polyamide resin, a polyurethane resin, a polyester resin, an epoxy resin, a polyketone resin, a polycarbonate resin or the like, a polyvinyl ketone resin, a polystyrene resin, Examples thereof include vinyl polymers such as polyacrylamide resin.

Next, the resistance control type surface protective layer in which the resistance control agent is dispersed will be described.
As the resistance control agent, particles of carbon black, metal, metal oxide or the like can be used. The particle diameter is preferably 100 nm or less.
Examples of metal oxides include titanium oxide, zinc oxide, tin oxide, antimony oxide coated tin oxide, silicon oxide, iron oxide, aluminum oxide, cerium oxide, yttrium oxide, silicon oxide, zirconium oxide, iron oxide, magnesium oxide, oxidation Copper, manganese oxide, molybdenum oxide, tungsten oxide, solid solution of barium sulfate and antimony oxide, mixture of the above metal oxides, titanium oxide, tin oxide, zinc oxide or barium sulfate in a single particle The thing mixed and the thing which coat | covered said metal oxide to the single particle of a titanium oxide, a tin oxide, zinc oxide, or barium sulfate is mentioned.
Further, metallocene compounds such as N, N′-dimethylferrocene, N, N′-diphenyl-N, N′-bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine, etc. An aromatic amine compound or the like can be used as a resistance control agent (particle) adjuster.
Furthermore, these metal oxides can be surface-treated with organic compounds such as silane coupling agents, titanium coupling agents, and zirconium coupling agents to improve various properties such as dispersibility, if necessary. .

  Among these, it is preferable to use a metal oxide having a particle size of 100 nm or less for the resistance control type surface protective layer. Thereby, the resistance control type surface protective layer is rich in transparency, and even if a thick film is formed, the decrease in the transmittance is small, so that the decrease in sensitivity can be suppressed. Therefore, in addition to the high wear resistance strength, it is possible to further improve the life of the intermediate transfer member in combination with the effect of increasing the film thickness.

Resistance control type surface protective layer is acetal resin such as polyvinyl butyral, polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinyl acetate resin, A film is formed by dispersing the above resistance control agent (particles) in a binder resin such as vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol resin, phenol-formaldehyde resin, melamine resin. .
The resistance control agent is dispersed in the binder resin to form a film, but the addition amount of the resistance control agent is adjusted in order to obtain an appropriate coating film resistance. As the addition amount of the resistance control agent, 10 to 60% by volume, preferably 20 to 50% by volume is contained in the binder resin solid content.

Subsequently, a charge transporting surface protective layer made of a polymer compound imparted with charge transporting property will be described.
As the charge transporting surface protective layer, a polymer compound having a charge transporting property in the molecule (hereinafter sometimes referred to as a charge transporting polymer compound) or a tough material such as a silicone hard coat agent is used. A resin component having a charge transporting function by dispersing a low-molecular charge transporting agent in the coating agent at the molecular level can be used.
Examples of the charge transporting polymer compound include those in which a charge transporting group is added in the molecule of the silicone polymer. In addition, a polymer compound containing a group having a charge transport ability such as polyvinylcarbazole in the side chain, a polymer containing a group having a charge transport ability as disclosed in JP-A-5-232727, etc. in the main chain A compound, polysilane, etc. can also be mentioned.
In addition, as the charge transporting polymer compound, a block copolymer or a graft copolymer composed of a charge transporting block and an insulating block can be used. When the charge transporting polymer compound contains a triarylamine structure as a repeating unit, it is preferable because it has a high charge transporting ability and favorable mechanical properties, and the triarylamine structure is not a pendant type, More preferably, it is contained in the main chain. In the case of the pendant type, pendants are often associated with each other to form charge traps and deteriorate the charge transport property, but such problems can be avoided by being contained in the main chain.
Furthermore, when the charge transporting polymer compound contains a triarylamine structure in the main chain, the main chain is represented by the following general formula (1) or the following general formula (2). It is preferable that a triarylamine structure containing at least one of the above structures as a repeating unit is contained.

However, in said general formula (1), Ar < ¹ > and Ar < ² > show a substituted or unsubstituted aryl group each independently, X < ¹ > is a bivalent hydrocarbon group or hetero atom containing hydrocarbon which has an aromatic ring structure. X ² and X ³ each independently represents a substituted or unsubstituted arylene group, and L ¹ represents a divalent hydrocarbon group or a heteroatom-containing hydrocarbon group which may contain a branched or ring structure. M and n each represents an integer selected from 0 or 1.

However, in said general formula (2), Ar < ³ > and Ar < ⁴ > show a substituted or unsubstituted aryl group each independently, L < ² > is a trivalent hydrocarbon group or hetero atom containing hydrocarbon which has an aromatic ring structure. Indicates a group.

In the general formula (1), Ar ¹ and Ar ² are each independently selected from a substituted or unsubstituted aryl group. Specific examples of the aryl group include a phenyl group, a biphenyl group, a naphthyl group, and a pyrenyl group. Is mentioned. Examples of the substituent include a methyl group, an ethyl group, a methoxy group, and a halogen atom.

X ¹ is selected from a divalent hydrocarbon group having an aromatic ring structure or a heteroatom-containing hydrocarbon group. Specific examples of X ¹ include a phenylene group, a biphenylene group, a terphenylene group, a naphthylene group, a methylenediphenyl group, a cyclohexylidenediphenyl group, an oxydiphenyl group, a thiodiphenyl group, and the like, and methyl-substituted products and ethyl-substituted products thereof. In particular, a substituted or unsubstituted biphenylene group is particularly preferable from the viewpoint of charge transportability.

X ² and X ³ are each independently selected from a substituted or unsubstituted arylene group, specifically, a phenylene group, a biphenylene group, a terphenylene group, a naphthylene group, and the like, and methyl-substituted, ethyl-substituted, A methoxy substituted body, a halogen substituted body, etc. are mentioned.

L ¹ is selected from a divalent hydrocarbon group or a heteroatom-containing hydrocarbon group which may contain a branched or ring structure, and is optional as long as it exhibits at least one of the above-mentioned preferable characteristics. And those having a bonding group selected from an ester bond, a carbonate bond, a siloxane bond and the like and having 20 or less carbon atoms. Specific examples of L ¹ include divalent linking groups represented by the following (3-1) to (3-8).

In the general formula (2), Ar ³ and Ar ⁴ are each independently selected from a substituted or unsubstituted aryl group. Specific examples of the aryl group include a phenyl group, a biphenyl group, a naphthyl group, and a pyrenyl group. Can be mentioned. Moreover, as a substituent, a C1-C12 alkyl group or an alkoxy group, a diarylamino group, a halogen atom, etc. are mentioned.

L ² is selected from a trivalent hydrocarbon group having an aromatic ring structure or a heteroatom-containing hydrocarbon group, and may be any one as long as it exhibits at least one of the above preferred characteristics, but has a carbon number of 20 or less Is preferred. Specific examples thereof include linking groups represented by the following (3-9) to (3-13).

Moreover, it is particularly preferable in terms of mechanical properties and charge transport ability that L ¹ in the general formula (1) or L ² in the general formula (2) has an ester bond.

  As a binder resin when using this charge transporting polymer compound, polyamide resin, polyvinyl acetal resin, polyurethane resin, polyester resin, epoxy resin, polyketone resin, polycarbonate resin, polyvinyl ketone resin, polystyrene resin, polyacrylamide resin, Known resins such as a polyimide resin and a polyamideimide resin can be used. These can also be used by cross-linking each other as necessary.

  Here, the surface protective layer in the present invention is preferably made of a resin having a certain degree of hardness in order to prevent the conductive foreign matter penetrating into the intermediate transfer member from the outside with the surface protective layer.

The surface protective layer is formed by preparing a coating solution containing the components constituting each surface protective layer described above, and applying and drying it. The method of dispersing and blending the resistance control agent and the charge transporting polymer compound is the same as the method for forming the charge transport layer described above.
The thickness of the surface protective layer is preferably 0.1 to 20 μm, more preferably 1 to 10 μm. Coating methods of the coating solution for forming this surface protective layer include blade coating method, wire bar coating method, spray coating method, dip coating method, ring coating method, bead coating method, air knife coating method, curtain coating method. A usual method such as can be used.
Moreover, as a solvent used for the coating liquid for forming the surface protective layer, a normal organic solvent such as dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, toluene, alcohol or the like may be used alone or in combination. However, it is preferable to use a solvent that hardly dissolves the photosensitive layer to which the coating solution is applied.

[Base material]
Next, the base material constituting the intermediate transfer member of the present invention will be described.
There is no restriction | limiting in particular in the shape in the base material in this invention, It can comprise in the shape of a belt or a drum.
The base material in the present invention is preferably composed of a thermosetting resin or a thermoplastic resin and has a Young's modulus of 1,000 Mpa or more from the viewpoint of color misregistration. The resin material constituting the substrate is not particularly limited as long as the above Young's modulus can be satisfied.
The base material in the present invention is preferably semiconductive having a volume resistivity of 1 × 10 ⁶ to 1 × 10 ¹³ Ωcm, and more preferably 1 × 10 ⁹ to 1 × 10 ¹² Ωcm. It is. When the volume resistivity of the base material is less than 1 × 10 ⁶ Ωcm, when this intermediate transfer member is applied to a tandem image forming apparatus described later, the resistance between each color of the primary transfer is low, so that the transfer portion In some cases, the necessary transfer voltage cannot be applied. Further, if it exceeds 1 × 10 ¹³ Ωcm, there may be a problem that the charge cannot be sufficiently removed.

  Specific examples of the resin material used for the substrate include, for example, polyimide resin, polyamideimide resin, fluorine resin, vinyl chloride vinyl acetate copolymer, polycarbonate (PC), polyethylene terephthalate (PET), and vinyl chloride. Examples thereof include resins, ABS resins, polymethyl methacrylate (PMMA), polyester resins such as polybutylene terephthalate (PBT), polyamide (PA), and the like. These may be used alone or in combination of two or more. Among these, polyimide resin and fluorine are not influenced by the drying temperature when coating and drying the above-described charge transport layer, charge generation layer, and undercoat layer, and are excellent in both structural strength and bending fatigue. System resins are preferably used.

As a polyimide resin suitable for the substrate, for example, an aromatic tetracarboxylic acid component and an aromatic diamine component are obtained by reacting in an organic polar solvent. As aromatic tetracarboxylic acid components, pyromellitic acid, naphthalene-1,4,5,8-tetracarboxylic acid, naphthalene-2,3,6,7-tetracarboxylic acid, 2,3,5,6-biphenyl Tetracarboxylic acid, 2,2 ′, 3,3′-biphenyltetracarboxylic acid, 3,3 ′, 4,4′-biphenyltetracarboxylic acid, 3,3 ′, 4,4′-diphenylethertetracarboxylic acid Acid, 3,3 ′, 4,4′-benzophenonetetracarboxylic acid, 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic acid, 3,3 ′, 4,4′-azobenzenetetracarboxylic acid, bis ( 2,3-dicarboxyphenyl) methane, bis (3,4-dicarboxyphenyl) methane, β, β-bis (3,4-dicarboxyphenyl) propane, β, β-bis (3,4-dicarboxy) Phenyl) Kisa has full Oro propane or a mixture of these tetracarboxylic acids. The aromatic diamine component is not particularly limited, and m-phenyldiamine, p-phenyldiamine, 2,4-diaminotoluene, 2,6-diaminotoluene, 2,4-diaminochlorobenzene, m-xylylenediamine P-xylylenediamine, 1,4-diaminonaphthalene, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,4′-diaminonaphthalenediphenyl, benzidine, 3,3-dimethylbenzidine, 3,3 '-Dimethoxybenzidine, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether (oxy-p, p'-dianiline; ODA), 4,4'-diaminodiphenyl sulfide, 3, 3′-diaminobenzophenone, 4,4′-diaminophenyl sulfone, 4,4′-diaminoazobenzene, , 4'-diaminodiphenylmethane, beta, beta-bis (4-amine phenyl) propane. Examples of the organic polar solvent include N-methyl-2-pyrrolidone, N, N-dimethylacetamide, dimethyl sulfoxide, hexamethylphosphortriamide and the like.
These organic polar solvents can be mixed with phenols such as cresol, phenol, and xylenol, and hydrocarbons such as hexane, benzene, and toluene as necessary. Used as a mixture of more than one kind.
It is a preferable aspect that the substrate in the present invention is composed of a polyimide resin obtained by dispersing the following conductive agent and has the above-described volume resistivity.

Examples of the fluorine-based resin suitable for the substrate include, for example, polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer [Poly (VdF-TFE)], Ethylene-tetrafluoroethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) Etc. Among these, polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, and Poly (VdF-TFE) are preferably used.
It is a preferable aspect that the base material in the present invention is composed of a fluorine resin in which the following conductive agent is dispersed and has the above volume resistivity.

(Conductive agent)
In order to obtain the above-described volume resistivity (electrical resistance), the base material in the present invention includes one or two conductive agents that impart electron conductivity and ionic conductivity as necessary. Add more than one kind in combination.

As an electron conductive conductive agent, metal or alloy such as carbon black, graphite, aluminum, nickel, copper alloy, tin oxide, zinc oxide, kalim titanate, tin oxide-indium oxide or tin oxide-antimony oxide composite oxide, etc. And metal oxides. Examples of the ion conductive conductive agent include sulfonates and ammonia salts, and various surfactants such as cationic, anionic, and nonionic surfactants.
Furthermore, there is a method of blending conductive polymers. Examples of the conductive polymer include various (for example, styrene) copolymers with (meth) acrylates that bind a quaternary ammonium base to a carboxyl group, and a quaternary ammonium base. Polymers that bind quaternary ammonium bases, such as copolymers of maleimide and methacrylate, that bind to styrene, polymers that bind alkali metal salts of sulfonic acids such as sodium polysulfonate, hydrophilic units of at least alkyl oxide in the molecular chain Such as polyethylene oxide, polyethylene glycol-based polyamide copolymer, polyethylene oxy-epichlorohydrin copolymer polyether amide imide, block type polymer having polyether as a main segment, polyaniline, Li thiophene, can be exemplified polyacetylene, polypyrrole, polyphenylene vinylene and the like, can be used these conductive polymers undoped state, or in a doped state. The above-described electrical resistance can be stably obtained by using one or two or more of the above-mentioned conductive agent, conductive polymer, or surfactant.

  The conductive agent in the present invention has good dispersibility in the resin composition, good dispersion stability is obtained, resistance variation can be reduced, electric field dependency is also reduced, and further, depending on the transfer voltage. Acidic carbon black having a pH of 5 or less is preferred because the electric field concentration is less likely to improve the stability of electrical resistance over time.

-Acidic carbon black of pH 5 or less-
Acidic carbon black having a pH of 5 or less can be produced by oxidizing carbon black to give a carboxyl group, a quinone group, a lactone group, a hydroxyl group, or the like. This oxidation treatment is an air oxidation method in which contact is made with air in a high-temperature atmosphere to react, a method of reacting with nitrogen oxides or ozone at room temperature, and air oxidation at high temperature, followed by ozone oxidation at a low temperature. It can be performed by a method or the like. Specifically, acidic carbon black having a pH of 5 or less can be produced by a contact method. Examples of the contact method include a channel method and a gas black method. Acidic carbon black can also be produced by a furnace black method using gas or oil as a raw material. Further, if necessary, after performing these treatments, a liquid phase oxidation treatment with nitric acid or the like may be performed. Acidic carbon black can be produced by a contact method, but is usually produced by a closed furnace method. In the furnace method, usually only carbon black having a high pH and a low volatile content is produced, but the pH can be adjusted by subjecting it to the above-mentioned liquid phase acid treatment. For this reason, in the present invention, carbon black obtained by furnace method production and adjusted to have a pH of 5 or less by post-treatment is considered to be included in acidic carbon black having a pH of 5 or less.

  The pH value of the acidic carbon black in the present invention is preferably pH 5.0 or less, more preferably pH 4.5 or less, and further preferably pH 4.0 or less. Acidic carbon having a pH of 5.0 or less has an oxygen-containing functional group such as a carboxyl group, a hydroxyl group, a quinone group, and a lactone group, so that the dispersibility in the resin is good and good dispersion stability is obtained. The variation in resistance of the transfer body can be reduced, and the electric field dependency is also reduced, so that the electric field concentration due to the transfer voltage is less likely to occur.

  The pH of the carbon black is determined by adjusting an aqueous suspension and measuring with a glass electrode. Further, the pH of the carbon black can be adjusted by conditions such as the treatment temperature and treatment time in the oxidation treatment step.

The oxidized carbon black having a pH of 5.0 or less preferably has a volatile component content of 1 to 25%, more preferably 3 to 20%, and 3.5 to 15%. Is more preferable. When the content of the volatile component is less than 1%, the effect of the oxygen-containing functional group adhering to the outside is lost, and the dispersibility in the binder resin may be reduced. On the other hand, if the content of the volatile component is higher than 25%, it may be decomposed when dispersed in the resin composition, or the amount of water adsorbed on the outer oxygen-containing functional group is increased. The appearance of the substrate in the present invention may be deteriorated.
On the other hand, the dispersion | distribution in the said resin composition can be made more favorable because content of the said volatile component shall be 1-25%. The content of the volatile component can be determined from the ratio of organic volatile components (carboxyl group, hydroxyl group, quinone group, lactone group, etc.) that come out when carbon black is heated at 950 ° C. for 7 minutes.

  The substrate in the intermediate transfer member of the present invention may contain two or more types of carbon black. At that time, these carbon blacks are preferably substantially different in conductivity from each other, for example, those having different physical properties such as degree of oxidation treatment, DBP oil absorption, specific surface area by BET method utilizing nitrogen adsorption, etc. Use. Thus, when adding two or more types of carbon blacks having different electrical conductivity, for example, after adding carbon black that exhibits high electrical conductivity preferentially, carbon black with low electrical conductivity is added to increase the surface resistivity. It is possible to adjust. Even when two or more types of carbon black are contained in this way, at least one of them can be mixed and dispersed by using an oxidation-treated carbon black having a pH of 5.0 or less.

  Specific examples of acidic carbon black having a pH of 5.0 or less include “Printex 150T” (pH 4.5, volatile content 10.0%) and “Special Black 350” (pH 3.5, volatile content) manufactured by Degussa. 2.2%), "Special Black 100" (pH 3.3, volatile matter 2.2%), "Special Black 250" (pH 3.1, volatile matter 2.0%), "Special Black 5" (PH 3.0, volatile content 15.0%), "Special Black 4" (pH 3.0, volatile content 14.0%), "Special Black 4A" (pH 3.0, volatile content 14.0%) "Special Black 550" (pH 2.8, volatile content 2.5%), "Special Black 6" (pH 2.5, volatile content 18.0%), "Color Black FW200" (pH 2.5, Volatilization 20.0%), “Color Black FW2” (pH 2.5, volatile content 16.5%), “Color Black FW2V” (pH 2.5, volatile content 16.5%), “MONARCH1000” manufactured by Cabot Corporation. (PH 2.5, volatile content 9.5%), “MONARCH 1300” manufactured by Cabot (pH 2.5, volatile content 9.5%), “MONARCH 1400” manufactured by Cabot (pH 2.5, 9.0% volatile content) “MOGUL-L” (pH 2.5, volatile matter 5.0%), “REGAL400R” (pH 4.0, volatile matter 3.5%), and the like.

  The acidic carbon black having a pH of 5.0 or less is more conductive than the general carbon black because it has better dispersibility in the resin composition due to the effect of the oxygen-containing functional group present on the surface as described above. It is preferable to increase the addition amount as a powder. Thereby, since the amount of carbon black in the base material increases, the effect of using the oxidized carbon black that can suppress the in-plane variation of the electric resistance value can be maximized.

  As content of the said acidic carbon black below pH5.0 with respect to the base material in this invention, what is necessary is just to satisfy said preferable volume resistivity (electrical resistance), Specifically, it is 10-30 mass%. In this case, the effect of acidic carbon black, such as suppressing in-plane variation in the surface resistivity of the intermediate transfer member, can be exhibited, which is preferable. If the acidic carbon black having a pH of 5.0 or less is less than 10% by mass, the uniformity of electrical resistance is lowered, and the in-plane unevenness of the surface resistivity and the electric field dependency may increase. On the other hand, if the content of the oxidized carbon black having a pH of 5.0 or less exceeds 30% by mass, it may be difficult to obtain a desired resistance value. Further, it is more preferable to contain 18-30% by mass of the oxidized carbon black having a pH of 5.0 or less. By containing 18-30% by mass of the oxidized carbon black having a pH of 5.0 or less, the effect is maximized. It is possible to achieve the limit, and it is possible to reduce in-plane resistance unevenness and electric field dependency.

[Volume resistivity of intermediate transfer member]
In the present invention, the surface layer composed of the above-described photoconductive layer is a dielectric in a state where it is not irradiated with light. Therefore, as described above, the volume resistivity is 1 × 10 ^13.5 Ωcm or more, preferably 1 × 10 ¹⁴ Ωcm or more. Moreover, in the state irradiated with light, resistivity changes and shows electroconductivity.
On the other hand, even when the photoconductive layer is composed of a charge transport layer and a charge generation layer, the volume resistivity is 1 × 10 6 as described above because the charge transport layer functions as a dielectric when not irradiated with light. ^13.5 Ωcm or more, preferably 1 × 10 ¹⁴ Ωcm or more. Further, in the state of being irradiated with light, the charge generation layer generates charges, so that the resistivity changes and exhibits conductivity.

The volume resistivity of the intermediate transfer member itself having such a photoconductive layer is preferably 1 × 10 ^13.5 to 1 × 10 ¹⁶ Ωcm in a state where light is not irradiated from the viewpoint of toner transfer efficiency and retention. × 10 ¹⁴ to 1 × 10 ¹⁶ Ωcm is more preferable.
In addition, when the intermediate transfer body itself is irradiated with light, the resistivity changes and exhibits conductivity.

The volume resistivity of the intermediate transfer member of the present invention can be measured according to JIS K 6991 using a circular electrode (for example, HR probe of Hiresta IP manufactured by Mitsubishi Yuka Co., Ltd.). A method for measuring the volume resistivity will be described with reference to the drawings. FIG. 3 is a schematic plan view (A) and a schematic cross-sectional view (B) showing an example of a circular electrode.
The circular electrode shown in FIG. 3 includes a first voltage application electrode A ′ and a second voltage application electrode B ′. The first voltage application electrode A ′ has a cylindrical electrode part C ′ and a cylindrical shape having an inner diameter larger than the outer diameter of the cylindrical electrode part C ′ and surrounding the cylindrical electrode part C ′ at a constant interval. Ring-shaped electrode portion D ′. The intermediate transfer body 1 is sandwiched between the cylindrical electrode portion C ′ and the ring-shaped electrode portion D ′ and the second voltage application electrode B ′ in the first voltage application electrode A ′, and the circle in the first voltage application electrode A ′. The current I (A) that flows when the voltage V (V) is applied between the columnar electrode portion C ′ and the second voltage application electrode B ′ is measured, and the volume of the intermediate transfer body 1 is calculated by the following equation (2). The resistivity ρv (Ωcm) can be calculated. Here, in the following formula (2), t represents the thickness of the intermediate transfer member 1.
Formula (2) ρv = 19.6 × (V / I) × t
In addition, the volume resistivity of the said photoconductive layer or a base material can also be measured by the same method.

[Surface micro hardness of intermediate transfer member]
In the intermediate transfer member of the present invention, the surface microhardness on the surface layer (photoconductive layer) side is preferably 30 degrees or less, and more preferably 25 degrees or less. The present inventors have found that there is a very accurate correlation between the surface microhardness on the surface layer side and the generation level of the holocharacter. That is, the intermediate transfer member of the present invention has a surface layer-side microhardness of 30 degrees or less, more preferably 25 degrees or less. The surface (surface layer) is deformed, whereby the pressing force concentrated on the semiconductive toner is dispersed. For this reason, the toner does not aggregate, and image quality defects such as a holocharacter in which the line image disappears are not generated.

The surface microhardness can be determined by a method of measuring how much the indenter has entered the sample. A method for measuring the surface microhardness will be described. FIG. 4 is a schematic diagram showing the measurement principle of the surface microhardness on the surface layer side of the intermediate transfer member of the present invention. In FIG. 4, 10 represents a needle-like indenter, and 12 represents the outermost surface layer on the surface layer side. The arrow P means a load applied to the needle-like indenter 10.
When measuring the surface microhardness, the tip of the needle-shaped indenter 10 having a predetermined shape is pressed against the surface portion of the outermost surface layer 12 on the surface layer side until the load (mN) is changed from the load 0 to the predetermined load P. When the biting depth in the vertical direction into the outermost surface layer 12 on the surface layer side of the needle-like indenter 10 at this time is D (μm), the surface microhardness DH is expressed by the following formula (3).
Formula (3) DH≡αP / D ²
Here, α in the expression (3) is a constant depending on the shape of the indenter, and α = 3.8854 (used indenter: in the case of a triangular pyramid indenter).

This surface microhardness is the hardness obtained from the excessive weight and indentation depth in the process of indenting the indenter, and represents the strength characteristics of the material including not only plastic deformation of the sample but also elastic deformation. is there. In addition, the measurement area is very small, and more accurate hardness measurement is possible within a range close to the toner particle diameter.
The surface microhardness on the surface layer side in the present invention was determined by the following method. A sheet of surface layer material constituting the intermediate transfer member is cut into about 5 mm square, and the small piece is fixed to the glass plate with an instantaneous adhesive. The surface microhardness of this sample is measured using an ultra microhardness meter DUH-201S (manufactured by Shimadzu Corporation). The measurement conditions are as follows.
Measurement environment: 23 ° C, 55% RH
Working indenter: Triangular pyramid indenter Test mode: 3 (soft material test)
Test load: 6.9 × 10 ⁻³ N (0.70 gf)
Load speed: 0.142 × 10 ⁻³ N (0.0145 gf / sec)
Holding time: 5 sec

[Thickness of intermediate transfer member]
When the intermediate transfer member of the present invention is used as an intermediate transfer belt, the total thickness is preferably in the range of 0.03 to 1.0 mm, and in the range of 0.05 to 0.8 mm. More preferably, it is still more preferably in the range of 0.1 to 0.5 mm.
When the total thickness is less than 0.03 mm, belt expansion / contraction (displacement amount) due to disturbance (load fluctuation) during driving of the belt increases, and it may be impossible to stably obtain good image quality. On the other hand, when the total thickness exceeds 1.0 mm, the deformation amount of the outer surface of the belt at a belt bending portion such as a drive system roll becomes large, and a good image quality may not be obtained. Further, the deformation amount between the outer side and the inner side of the belt increases, and there may be a problem that the belt breaks due to local repeated stress.
The thickness of the surface layer (photoconductive layer) is preferably in the range of 10 to 80% of the total thickness of the intermediate transfer member, and more preferably in the range of 20 to 60%.

<Image forming apparatus>
The image forming apparatus of the present invention is an intermediate transfer body type image forming apparatus, and uses the above-described intermediate transfer body of the present invention as the intermediate transfer body, and transfers a toner image formed on the surface of the intermediate transfer body to a transfer material. The other configuration is not particularly limited as long as it includes a light neutralizing unit that neutralizes the surface of the intermediate transfer member by light irradiation after the transfer. For example, a normal monocolor image forming apparatus that contains only a single color toner in the developing device, or a color image in which a toner image carried on an image carrier such as a photosensitive drum is repeatedly subjected to primary transfer sequentially to an intermediate transfer member Any of a forming apparatus, a tandem type color image forming apparatus in which a plurality of image carriers having developing units for respective colors are arranged in series on an intermediate transfer member may be used.
The image forming apparatus of the present invention may be configured to include a plurality of intermediate transfer members. In that case, in the image forming apparatus of the present invention, at least one of the plurality of intermediate transfer members may be the above-described intermediate transfer member of the present invention, and all are preferably the intermediate transfer member of the present invention.

In the present invention, the term “transfer material” refers to an intermediate transfer member used for transferring a toner image on the surface of an intermediate transfer member indirectly to a recording material such as recording paper or an OHP sheet, or when transferring directly. It means both of the recording materials used in the above. Accordingly, the image forming apparatus of the present invention has a plurality of intermediate transfer members that transfer the toner image formed on the surface of the intermediate transfer member of the present invention to another intermediate transfer member (transfer material), for example. May be provided. Also in this case, in the image forming apparatus of the present invention, at least one of the plurality of intermediate transfer members may be the above-described intermediate transfer member of the present invention, and all are preferably the intermediate transfer member of the present invention.
In the image forming apparatus described later with reference to FIGS. 5 and 6, the “transfer material” is a recording material.

As an example, a color image forming apparatus in which primary transfer is sequentially repeated using an intermediate transfer body of the present invention, the surface layer of which is a photoconductive layer, as an intermediate transfer belt is shown.
FIG. 5 is a schematic diagram for explaining a main part of the image forming apparatus of the present invention. The image forming apparatus includes a photosensitive drum 21 as an image carrier, an intermediate transfer belt 22 as an intermediate transfer member, a static elimination lamp 91 (light static elimination means) for neutralizing the intermediate transfer belt 22, and a bias roller 23 (transferred electrode). Second transfer means), a paper tray 24 for supplying recording paper as a transfer medium, a developing device 25 using Bk (black) toner, a developing device 26 using Y (yellow) toner, a developing device 27 using M (magenta) toner, C (Cyan) toner developing device 28, intermediate transfer body cleaner 29, peeling claw 33, belt rollers 41, 43 and 44, backup roller 42, conductive roller 45 (first transfer means), electrode roller 46, cleaning blade 51, A recording sheet 61, a pickup roller 62, and a feed roller 63 are provided. Note that the intermediate transfer belt 22 shown in FIG. 5 is the above-described intermediate transfer member of the present invention.

  Next, the configuration of the image forming apparatus shown in FIG. 5 will be described. Around the photosensitive drum 21, a black developing unit 25, a yellow developing unit 26, a magenta developing unit 27, and a cyan developing unit 28 are arranged in this order along the arrow A direction. In addition, a conductive roller 45 is disposed on the opposite side of the photosensitive drum 21 from the side where the four color developing devices are disposed so that the intermediate transfer belt 22 is sandwiched between the conductive roller 45 and the photosensitive drum 21. ing.

The intermediate transfer belt 22 is stretched by a conductive roller 45, a belt roller 41, a belt roller 43, a backup roller 42, and a belt roller 44 that are sequentially arranged in the direction of arrow B in contact with the inner peripheral surface thereof. An intermediate transfer body cleaner 29 is disposed on the opposite side of the belt roller 44 across the belt 22. Further, the separation claw 33 is disposed so as to contact the outer peripheral surface of the portion of the intermediate transfer belt 22 stretched by the backup roller 42 and the belt roller 44.
In addition, a neutralizing lamp 91 is installed on the outer peripheral surface side of the intermediate transfer belt 22 between the belt roller 44 and the conductive roller 45, and is grounded so as to contact the inner peripheral portion ( (Not shown) A conductive member 90 for static elimination is provided.

  The backup roller 42 is in pressure contact with the bias roller 23 via the intermediate transfer belt 22, and the recording paper 61 can be inserted between the backup roller 42 (the intermediate transfer belt 22 pressed against) and the bias roller 23. It is. A cleaning blade 51 is provided around the bias roller 23 so as to be in contact with this surface. Further, an electrode roller 46 is disposed in contact with the backup roller 42 on the substantially opposite side of the backup roller 42 to the side where the bias roller 23 is disposed.

  In a direction in which the paper 41 passes between the backup roller 42 and the bias roller 23, a pair of mutually contacting feed rollers 63 is disposed, and the paper 41 can be inserted between the two feed rollers 63. Further, on the opposite side of the pair of feed rollers 63 from the side on which the backup roller 42 and the bias roller 23 are provided, a paper tray 24 that stocks the recording paper 61 and a pair of feed rollers that feed the recording paper 61 from the paper tray 24. A pickup roller for supplying to the contact portion 63 is disposed.

  Next, image formation using the image forming apparatus shown in FIG. 5 will be described. First, the photosensitive drum 21 rotates in the direction of arrow A, and its surface is uniformly charged by a charging device (not shown). An electrostatic latent image of the first color (for example, Bk) is formed on the charged photosensitive drum 21 by image writing means such as a laser writing device. The electrostatic latent image is developed with toner by the black developing device 25 to form a visualized toner image T. The toner image T reaches the primary transfer portion where the conductive roller 45 (first transfer means) is disposed by the rotation of the photosensitive drum 21, and an electric field having a reverse polarity is applied to the toner image T from the conductive roller 45. Thus, the toner image T is primarily transferred by the rotation of the intermediate transfer belt 22 in the direction of arrow B while being electrostatically attracted to the intermediate transfer belt 22.

Thereafter, similarly, a second color toner image, a third color toner image, and a fourth color toner image are sequentially formed and superimposed on the intermediate transfer belt 22 to form a multiple toner image.
The multiple toner image transferred to the intermediate transfer belt 22 reaches the secondary transfer portion where the bias roller 23 (second transfer means) is installed by the rotation of the intermediate transfer belt 2. The secondary transfer unit includes a bias roller 23 installed on the surface side on which the toner image of the intermediate transfer belt 22 is carried, a backup roller 42 disposed so as to face the bias roller 23 from the back side of the intermediate transfer belt 22, and It is composed of an electrode roller 46 that rotates in pressure contact with the backup roller 42.

  The recording paper 61 is picked up one by one from the recording paper bundle stored in the paper tray 24 by the pickup roller 62, and is fed at a predetermined timing between the intermediate transfer belt 22 and the bias roller 23 of the secondary transfer portion by the feed roller 63. It is sent by. The toner image carried on the intermediate transfer belt 22 is transferred to the fed recording paper 61 by the pressure contact conveyance by the bias roller 23 and the backup roller 42 and the rotation of the intermediate transfer belt 22.

  The recording paper 61 onto which the toner image has been transferred is peeled from the intermediate transfer belt 22 by operating the peeling claw 33 in the retracted position until the primary transfer of the final toner image is completed, and is conveyed to a fixing device (not shown). The toner image is fixed by heat treatment to be a permanent image. The intermediate transfer belt 22 having completed the transfer of the multiple toner image to the recording paper 61 is subjected to removal of residual toner by an intermediate transfer body cleaner 29 provided on the downstream side of the secondary transfer portion to prepare for the next transfer. The bias roller 23 is attached so that a cleaning blade 51 made of polyurethane or the like is always in contact therewith, and foreign matters such as toner particles and paper dust adhered by transfer are removed.

  In the case of transfer of a single color image, the primary transferred toner image T is immediately secondarily transferred and conveyed to the fixing device. In the case of transfer of a multicolor image by superimposing a plurality of colors, the toner image of each color is transferred to the primary transfer unit. Therefore, the rotation of the intermediate transfer belt 22 and the photosensitive drum 21 is synchronized so that the toner images of the respective colors do not shift so as to match exactly. In the secondary transfer portion, an output pressure (transfer voltage) having the same polarity as the polarity of the toner image is applied to the electrode roller 46 that is in pressure contact with the backup roller 42 that is disposed opposite to the bias roller 23 via the intermediate transfer belt 22. Then, the toner image is transferred to the recording paper 61 by electrostatic repulsion. Here, the charge of the intermediate transfer belt 22 is photo-discharged by irradiating the photoconductive layer (surface layer) with light by the charge-removing lamp 91 to develop conductivity.

Hereinafter, the transfer mechanism using the intermediate transfer belt 22 that is the intermediate transfer member of the present invention and the neutralization mechanism of the intermediate transfer belt 22 will be described in more detail with reference to FIG. 5 again.
The intermediate transfer belt 22 shown in FIG. 5 includes a primary transfer area Q3 that contacts the surface of the photosensitive drum 21 of the image forming apparatus, a secondary transfer area Q4 that contacts the recording paper 61, and a static elimination area Q5 by the static elimination lamp 91. Are rotated in the direction of arrow B so as to pass sequentially. Here, the intermediate transfer belt 22 when passing through the primary transfer region Q3 and the secondary transfer region Q4 is not irradiated with light but is in a dielectric state. When the intermediate transfer belt 22 passes through the primary transfer region Q3, the toner image on the surface of the photosensitive drum 21 is primarily transferred, and the primary transferred toner image is transferred to the recording paper 61 when passing through the secondary transfer region Q4. Next transferred.
As described above, the intermediate transfer belt 22 which is the intermediate transfer body of the present invention has a surface layer (photoconductive layer) that is a dielectric material and has a high volume resistivity when not irradiated with light. In the next transfer, the transfer can be performed in the state of a dielectric (insulator). At this time, since there is little movement of charges along the surface of the surface layer (photoconductive layer) of the intermediate transfer belt 22, good transfer with less scattering of the toner image can be performed in the primary transfer region Q3 and the secondary transfer region Q4. It can be carried out.

In the image forming apparatus of the present invention, the toner does not matter whether the charging characteristic is negative or positive. However, for the sake of convenience, the description will be made using negative toner.
In the case of negatively charged toner, primary transfer is performed by applying a positive voltage to the conductive roller 45 (primary transfer means). As a result, the intermediate transfer belt 22 after the primary transfer accumulates positive charges due to the conductive roller 45 on the back side, and accumulates negative charges due to toner and counter charge on the front side. In order to obtain a color image, the primary transfer voltage is sequentially increased after the second color, and a plurality of color toner images may be formed on the intermediate transfer belt 22.

Subsequently, during the secondary transfer, when the toner image is transferred to the recording paper 61, non-uniform positive charges corresponding to the secondary transfer image are supplied to the front surface side of the intermediate transfer belt 22, and to the back surface side. Is supplied with a negative charge. The surface potential of the intermediate transfer belt 22 after the secondary transfer is − (minus) when the secondary transfer voltage is lower than the primary transfer voltage, and when the secondary transfer voltage is higher than the primary transfer voltage, + (Plus).
Here, when the primary transfer process of the next image is performed in a state where the surface potential of the intermediate transfer belt 22 remains, the image is blurred, scattered, and thickened due to the occurrence of primary transfer unevenness due to the non-uniformity of the accumulated charge. Etc. will occur. Further, if there is no neutralization mechanism on the surface of the intermediate transfer belt 22 and negative charges are accumulated even after the secondary transfer, the charges are accumulated every time the primary transfer and the secondary transfer are repeated. The surface potential of the image becomes excessively high-(minus) value (the back surface side is excessively high positive (positive) surface potential). Therefore, the required primary transfer voltage in the next image is also very high. End up.
For this reason, after the secondary transfer, it is necessary to keep the charge accumulated on the intermediate transfer belt 22 uniformly below a certain level. Here, the certain level is a level determined according to the surface potential of the photosensitive drum 21, the toner charge amount, the form of the pre-transfer area, and the like.

  In the present invention, since an intermediate transfer member having a surface layer composed of a photoconductive layer is used as the intermediate transfer belt 22, the surface charge of the intermediate transfer belt 22 is irradiated with light by a static elimination lamp 91 after secondary transfer. The accumulated charges can be easily removed by light. This is because the free carriers generated by the photoconductive substance in the intermediate transfer belt 22 absorbing light neutralize the opposing charges existing on the surface. The neutralizing lamp 91 only needs to have a light source having a wavelength in the photosensitivity region of the photoconductive substance added to the photoconductive layer, and its intensity and photo neutralization position may be determined as needed. As the static elimination lamp 91, for example, a red light LED can be used.

Further, the charge accumulated in the intermediate transfer belt 22 is subjected to light neutralization by the neutralization lamp 91 and then further transferred to the intermediate transfer by the grounded conductive member 90 for neutralization which is in contact with the inner peripheral portion of the intermediate transfer belt 22. It is preferable that the belt 22 is discharged out of the belt 22. Therefore, it is preferable that the static elimination conductive member 90 is provided on the downstream side of the static elimination lamp 91 in the rotation direction of the intermediate transfer belt 22 (the direction of arrow B in FIG. 5). Further, the neutralizing conductive member 90 can be disposed on either the back surface side or the front surface side of the intermediate transfer belt 22, and discharge (removal) of electric charges is performed by contacting the intermediate transfer belt 22. As the conductive member 90 for static elimination, an elastic roll (for example, an epichlorohydrin rubber roll with carbon black dispersion) in which a conductive agent whose volume resistivity is adjusted to 1 × 10 ⁵ to 1 × 10 ¹⁰ Ω is used is used. Can do. As described above, the conductive member 90 for charge removal may be in a roll shape, a blade shape, or a brush shape.

The neutralizing conductive member 90 can be arranged on either the back side or the front side of the intermediate transfer belt 22, and when placed on the back side, it can always be used in contact with the intermediate transfer belt 22. When arranged on the front surface side, it is arranged at a position away from the intermediate transfer belt 22 until the secondary transfer is completed at the time of multiple transfer of the color toner image, and is intermediate when performing static elimination after the completion of the secondary transfer. It is necessary to configure to contact the transfer belt 22.
In that case, a moving mechanism for moving the neutralizing conductive member 90 between a position in contact with the intermediate transfer belt 22 and a position away from the intermediate transfer belt 22 is required. Therefore, when the electrically conductive member 90 for static elimination is arranged so as to be always in contact with the back surface of the intermediate transfer belt 22, the moving mechanism is not necessary, the configuration is simplified, and the cost is advantageously reduced.

  From the above, the image forming apparatus of the present invention having the above-described configuration uses the intermediate transfer member of the present invention as the intermediate transfer belt 22, and further, a static elimination lamp that can easily remove the charge of the intermediate transfer belt 22. Since it also has 91 (light static elimination means), image quality defects due to toner scattering are remarkably reduced, and high-quality transfer image quality can be stably obtained.

Next, a tandem type color image forming apparatus having an intermediate transfer belt comprising the intermediate transfer member of the present invention and a plurality of image carriers having developing units for respective colors arranged in series on the intermediate transfer belt will be described. Will be described.
FIG. 6 is a schematic diagram showing another example of the image forming apparatus of the present invention. The image forming apparatus shown in FIG. 6 includes four toner cartridges 71, a pair of fixing rolls 72, a backup roll 73, a tension roll 74, a secondary transfer roll 75, a paper path 76, a paper tray 77, a laser generator 78, 4 Three photosensitive members 79, four primary transfer rolls 80, a drive roll 81, a transfer cleaner 82, four charging rolls 83, a photosensitive member cleaner 84, four developing devices 85, an intermediate transfer belt 86, and an intermediate transfer belt 86 are neutralized. A static elimination lamp 91 (light static elimination means) and the like are included as main constituent members. In the image forming apparatus shown in FIG. 6, the intermediate transfer member of the present invention is used as the intermediate transfer belt 86.

  Next, the configuration of the image forming apparatus shown in FIG. First, around the photoconductor 79, a primary transfer roll 80 and a photoconductor cleaner 84 arranged counterclockwise via a charging roll 83, a developing device 85, and an intermediate transfer belt 86 are arranged. The member forms a developing unit corresponding to one color. Each developing unit is provided with a toner cartridge 71 for replenishing the developer in the developing unit 85. The photosensitive member 79 of each developing unit is exposed to a photosensitive member between the charging roll 83 and the developing unit 85. A laser generator 78 capable of irradiating the surface of the body 79 with laser light corresponding to image information is provided.

  Four developing units corresponding to four colors (for example, cyan, magenta, yellow, and black) are arranged in series in a substantially horizontal direction in the image forming apparatus, and the photosensitive member 79 of the four developing units and the primary are arranged. An intermediate transfer belt 86 is provided so as to pass through the nip portion with the transfer roll 80. The intermediate transfer belt 86 is stretched by a backup roll 73, a tension roll 74, and a drive roll 81 provided on the inner peripheral side thereof in the following order in the counterclockwise direction. The four primary transfer rolls are located between the backup roll 73 and the tension roll 74. A transfer cleaner 82 for cleaning the outer peripheral surface of the intermediate transfer belt 86 is provided on the opposite side of the drive roll 81 with the intermediate transfer belt 86 in contact with the drive roll 81.

  A toner image formed on the outer peripheral surface of the intermediate transfer belt 86 on the surface of the recording paper conveyed from the paper tray 77 via the paper path 76 to the opposite side of the backup roll 73 via the intermediate transfer belt 86. A secondary transfer roll 75 for transferring the image is provided so as to be in pressure contact with the backup roll 73. A neutralizing lamp 91 is installed on the outer peripheral surface side of the intermediate transfer belt 86 between the backup roll 73 and the drive roll 81, and is grounded (not shown) so as to contact the inner peripheral surface. 90 is installed.

  Further, a paper tray 77 for stocking recording paper is provided at the bottom of the image forming apparatus, and a backup roll 73 and a secondary transfer roll 75 that constitute a secondary transfer unit from the paper tray 77 via a paper path 76 are provided. It can supply so that it may pass a press-contact part. The recording paper that has passed through the pressure contact portion can be further transported by a transport means (not shown) so as to pass through the pressure contact portions of the pair of fixing rolls 72, and can finally be discharged out of the image forming apparatus.

  Next, an image forming method using the image forming apparatus of FIG. 6 will be described. The toner image is formed for each developing unit. After uniformly charging the surface of the photoreceptor 79 rotating counterclockwise by the charging roll 83, the photoreceptor 79 charged by the laser generator 78 (exposure apparatus) is charged. A latent image is formed on the surface, and then the latent image is developed with a developer supplied from a developing device 85 to form a toner image, which is conveyed to a pressure contact portion between the primary transfer roll 80 and the photoreceptor 79. The transferred toner image is transferred to the outer peripheral surface of the intermediate transfer belt 86 rotating in the arrow A direction. The photosensitive member 79 after the toner image has been transferred is cleaned by the photosensitive member cleaner 84 with toner or dust attached to the surface thereof in preparation for the next toner image formation.

  The toner images developed for each color development unit are sequentially superimposed on the outer peripheral surface of the intermediate transfer belt 86 so as to correspond to the image information, and are conveyed to the secondary transfer unit by the secondary transfer roll 75. The image is transferred from the sheet tray 77 to the surface of the recording sheet conveyed via the sheet path 76. The recording paper on which the toner image has been transferred is further fixed by being heated by pressure when passing through the pressure contact portion of a pair of fixing rolls 72 constituting the fixing portion, and after the image is formed on the surface of the recording medium. Then, it is discharged out of the image forming apparatus.

  The intermediate transfer belt 86 that has passed through the secondary transfer portion further proceeds in the direction of arrow C, and charges accumulated by the charge removal lamp 91 and the charge removal conductive member 90 are discharged. Thereafter, after the outer peripheral surface is further cleaned by the transfer cleaner 82, it is prepared for the transfer of the next toner image.

The charge accumulated on the intermediate transfer belt 86 is transferred to the outside of the intermediate transfer belt 86 by the charge removal conductive member 90 in addition to the light charge removal by the charge removal lamp 91 as in the charge removal mechanism of the intermediate transfer belt 22 described above. It is preferable that the charge is removed by discharging the electric charge. The static elimination lamp 91 and the static elimination conductive member 90 used here are the same as the static elimination lamp 91 and the static elimination conductive member 90 in the image forming apparatus shown in FIG.
The relationship between the installation positions of the charge removal lamp 91 and the charge removal conductive member 90 is the same as the relationship between the charge removal lamp 91 and the charge removal conductive member 90 in the image forming apparatus shown in FIG.
Furthermore, also in the image forming apparatus shown in FIG. 6, for example, a red light LED can be used as the charge eliminating lamp 91. Moreover, the electrically conductive member 90 for charge removal can be disposed on either the back surface side or the front surface side of the intermediate transfer belt 86. Here, the electrically conductive member 90 for charge removal has a volume resistivity of 1 × 10 ⁵ to 1 ×. An elastic roll (for example, an epichlorohydrin rubber roll with carbon black dispersion) can be used by dispersing a conductive agent adjusted to 10 ¹⁰ Ω.

  As described above, the tandem image forming apparatus having the configuration uses the intermediate transfer member of the present invention as the intermediate transfer belt 86, and further, the charge eliminating lamp 91 that can easily remove the charge of the intermediate transfer belt 86. Since (light neutralization means) is also used, image quality defects due to toner scattering are remarkably reduced, and high-quality transfer image quality can be stably obtained.

  Furthermore, when the intermediate transfer member of the present invention is incorporated and used as an intermediate transfer belt in an image forming apparatus, it is preferable to use a spherical toner as the toner. By using spherical toner as the toner, the material constituting the transfer surface has a low surface hardness and a high volume resistance, thereby obtaining a high-quality transfer image quality free from image quality defects (holocharacter, blur, color registration). be able to.

However, the spherical toner means that its shape factor (SF) is 140-100. The shape factor is preferably from 130 to 100, and more preferably from 120 to 100. When this average shape factor (SF) is larger than 140, the transfer efficiency is lowered, and the deterioration of the image quality of the print sample can be visually confirmed.
Here, the shape factor (SF) is a factor defined by the following equation (1).
Formula (1)
(SF) = [(absolute maximum length of toner particles) ² × π × 100] / [(projection area of toner particles) × 4]
The absolute maximum length of the toner particles and the projected area of the toner particles are measured using a video camera with an optical microscope image of the toner dispersed on the slide glass using a Luzex image analyzer (manufactured by Nireco Corporation, FT). This was carried out by taking in a Luzex image analyzer and processing the image.

  The spherical toner contains at least a binder resin and a colorant. The spherical toner has a volume average particle diameter of 2 to 12 μm, preferably 2.5 to 9 μm, and more preferably 3 to 6 μm.

  Binder resins include styrenes such as styrene and chlorostyrene, monoolefins such as ethylene, propylene, butylene and isoprene, vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate and vinyl butyrate, and methyl acrylate. , Α-methylene aliphatic monocarboxylic esters such as ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate, vinyl Homopolymers and copolymers of vinyl ethers such as methyl ether, vinyl ethyl ether, and vinyl butyl ether, vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and vinyl isopropenyl ketone can be exemplified. Typical binder resins include polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer. , Polyethylene, polypropylene and the like. Furthermore, polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, paraffin wax, and the like can be given.

  Coloring agents include magnetic powders such as magnetite and ferrite, carbon black, aniline blue, calcoil blue, chrome yellow, ultramarine blue, dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, and lamp black. Rose Bengal, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 57: 1, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 17, C.I. I. Pigment blue 15: 1, C.I. I. Pigment Blue 15: 3 is a typical example.

  The spherical toner may be subjected to internal addition treatment or external addition treatment with a known additive such as a charge control agent, a release agent, and other inorganic fine particles. Typical examples of the release agent include low molecular weight polyethylene, low molecular weight polypropylene, Fischer-Tropsch wax, montan wax, carnauba wax, rice wax, and candelilla wax.

  Known charge control agents can be used, but azo metal complex compounds, metal complex compounds of salicylic acid, and resin type charge control agents containing polar groups can be used. When the toner is manufactured by a wet manufacturing method, it is preferable to use a material that is difficult to dissolve in water in terms of controlling ionic strength and reducing wastewater contamination.

As other inorganic fine particles, small-sized inorganic fine particles having an average primary particle diameter of 40 nm or less are used for the purpose of powder flowability, charge control, etc., and if necessary, larger diameters are used to reduce adhesion. These inorganic or organic fine particles may be used in combination. As these other inorganic fine particles, known ones can be used. Examples thereof include silica, alumina, titania, metatitanic acid, zinc oxide, zirconia, magnesia, calcium carbonate, magnesium carbonate, calcium phosphate, cerium oxide, and strontium titanate.
In addition, the surface treatment of the small-diameter inorganic fine particles is effective because the dispersibility becomes high and the effect of increasing the powder fluidity increases.

  The spherical toner is not particularly limited by the production method, and can be obtained by a known method. Specifically, for example, a kneading and pulverizing method in which a binder resin and a colorant and, if necessary, a release agent and a charge control agent are kneaded, pulverized and classified, and particles obtained by the kneading and pulverizing method are mechanically Method of changing shape by force or heat energy, emulsion polymerization of binder resin polymerizable monomer, dispersion of formed dispersion, colorant, release agent and charge control agent as required Liquid emulsion, agglomeration, heat fusion to obtain spherical toner, emulsion polymerization aggregation method, polymerizable monomer for obtaining binder resin, colorant, release agent if necessary, charge control agent A suspension polymerization method in which a solution such as a suspension is polymerized by suspending in an aqueous solvent, a binder resin and a colorant, and a release agent and a charge control agent as necessary are suspended in an aqueous solvent and granulated. Examples thereof include a dissolution suspension method. Further, a manufacturing method may be performed in which the spherical toner obtained by the above method is used as a core, and agglomerated particles are further adhered and heat-fused to give a core-shell structure. When the external additive is added, it can be produced by mixing the spherical toner and the external additive with a Henschel mixer or a V blender. In addition, when the spherical toner is manufactured by a wet method, it can be externally added by a wet method.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

<Example 1>
[Preparation of belt-shaped substrate]
(Preparation of polyamic acid solution (A))
N-methyl-2-pyrrolidone (NMP) solution of polyamic acid composed of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) and 4,4′-diaminodiphenyl ether (DDE) (manufactured by Ube Industries) To Euvarnish S (solid content: 18% by mass), 100 parts by mass of the solid content of the raw material capable of forming the polyimide resin in this solution, dry oxidized carbon black (SPECIAL BLACK4 (manufactured by Degussa, pH 3.0, volatile content: 14.0%)) was added to 23 parts by mass, and a collision type disperser (GeanusPY manufactured by Seanas) was used, and the pressure was 200 MPa, the minimum area was 1.4 mm ^{2 and} was divided into 2 parts. It was made to collide afterwards, and the passage which divided into 2 again was passed 5 times, it mixed, and the polyamic-acid solution (A) containing carbon black for base materials was obtained.

(Formation of base material)
The polyamic acid solution (A) containing carbon black is applied to the inner surface of the cylindrical mold so that the thickness of the coating film becomes 0.5 mm via a dispenser, and the mold is rotated at 1500 rpm for 15 minutes to obtain a uniform thickness. After forming a coating film having a temperature of 60 ° C. from the outside of the mold for 30 minutes while rotating the mold at 250 rpm, the mixture was heated at 150 ° C. for 60 minutes and then cooled to room temperature. A film was formed.
Thereafter, the film formed on the inner surface of the mold is peeled off, and this film is coated so as to cover the outer periphery of the metal core, and the temperature is increased to 400 ° C. at a rate of 2 ° C./min. For 30 minutes to remove the solvent and dehydrated ring-closing water remaining in the film and complete the imide conversion reaction. Thereafter, after cooling the metal core to room temperature, the polyimide film formed on the surface of the metal core was peeled off to obtain an endless belt-like base material having a thickness of 0.08 mm.
The obtained base material had a Young's modulus of 3,800 Mpa, a volume resistivity of 1 × 10 ^9.5 Ωcm, and a surface resistivity of 1 × 10 ¹² Ω / □.

In addition, the measurement of the volume resistivity and surface resistivity of the obtained base material was performed as follows.
(Volume resistivity)
As described above, the obtained base material was sandwiched between the circular electrodes shown in FIG. 3 (High Lester IP HR probe manufactured by Mitsubishi Yuka Co., Ltd.) and placed in a 22 ° C./55% RH environment. Then, a voltage of 100 (V) is applied between the cylindrical electrode portion C ′ and the second voltage application electrode B ′ in the first voltage application electrode A ′, and the above formula ( The volume resistivity ρv (Ωcm) was determined by 2).

(Surface resistivity)
The obtained base material is sandwiched at a predetermined position of a circular electrode (High Lester IP HR probe manufactured by Mitsubishi Yuka Co., Ltd.) shown in FIG. 3, and the first voltage is applied in a 22 ° C./55% RH environment. A voltage of 100 (V) is applied between the cylindrical electrode portion C ′ and the ring-shaped electrode portion D ′ of the applied electrode A ′, and the surface resistivity is calculated by the following formula (4) based on the current value after 10 seconds. ρs (Ω / □) was calculated.
Formula (4) ρs = π × (D + d) / (D−d) × (V / I)
Here, in following formula (4), d (mm) shows the outer diameter of cylindrical electrode part C '. D (mm) indicates the inner diameter of the ring-shaped electrode portion D ′.

[Formation of undercoat layer]
Zinc oxide (MZ300: manufactured by Teika Co., Ltd .: specific surface area value 30 m ² / g) was heated and dried at 150 ° C. for 5 hours, and then 100 parts by mass of zinc oxide was stirred and mixed with 500 parts by mass of toluene to obtain a silane coupling agent (KBM403: 5 parts by mass) (manufactured by Shin-Etsu Chemical Co., Ltd.) was added and stirred for 2 hours. Thereafter, toluene was distilled off under reduced pressure and baked at 150 ° C. for 2 hours.
60 parts by mass of the zinc oxide subjected to the surface treatment, 15 parts by mass of a curing agent blocked isocyanate (Sumijoule 3175, manufactured by Sumitomo Bayern Urethane Co., Ltd.) and 15 parts by mass of a butyral resin (BM-1, manufactured by Sekisui Chemical Co., Ltd.) A solution obtained by dissolving 38 parts by mass of a solution dissolved in 85 parts by mass of methyl ethyl ketone and 25 parts by mass of methyl ethyl ketone was dispersed using a 1 mmφ glass bead in a sand mill for 2 hours.
Dioctyltin dilaurate: 0.005 parts by mass and silicone oil SH29PA (manufactured by Toray Dow Corning Silicone): 0.01 parts by mass were added as catalysts to the resulting dispersion to obtain an undercoat layer coating solution.
This undercoat layer coating solution was applied to the surface of an endless belt-like substrate by dip coating, followed by drying and curing at 160 ° C. for 100 minutes to obtain an undercoat layer having a thickness of 20 μm.

[Formation of charge generation layer]
Next, at a Bragg angle (2θ ± 0.2 °) of an X-ray diffraction spectrum using Cukα rays as a charge generation material, at least 7.5 °, 9.9 °, 12.5 °, 16.3. 15 parts by mass of hydroxygallium phthalocyanine from which clear diffraction peaks are obtained at positions of 18.6 °, 25.1 ° and 28.1 °, butyral resin as a binder resin (BM-1, manufactured by Sekisui Chemical Co., Ltd.) A mixture consisting of 10 parts by mass and 300 parts by mass of n-butyl alcohol was dispersed in a sand mill for 4 hours.
The obtained dispersion was applied as a charge generation layer coating solution by dip coating on the surface of the undercoat layer and dried to form a charge generation layer having a thickness of 0.2 μm.

[Formation of charge transport layer]
Next, 2 parts by mass of di (3,4-dimethylphenyl) (4-phenylphenyl) amine and N, N′-diphenyl-N, N′-bis (3-methylphenyl)-[1,1′-biphenyl ] 4 parts of 4,4'-diamine and 6 parts by weight of bisphenol Z polycarbonate (molecular weight 40,000), 80 parts by weight of tetrahydrofuran, 0.2 parts by weight of 2,6-di-t-butyl-4-methylphenol To dissolve. The obtained liquid was applied as a charge transport layer coating solution by dip coating on the surface of the charge generation layer and dried at 120 ° C. for 40 minutes to form a charge transport layer having a thickness of 25 μm.
As a result, an intermediate transfer member of the present invention having the layer structure shown in FIG.

Here, the surface microhardness on the surface layer side of the intermediate transfer member in Example 1 was measured by the above-described measurement method (measurement conditions were the same as described above) using an ultra-micro hardness meter DUH-201S. It was a degree.
Further, the volume resistivity of the intermediate transfer member in Example 1 in a state where the intermediate transfer member was not irradiated with light was measured by the same method as the measurement method of the substrate, and found to be 1 × 10 ^13.8 Ωcm.

<Example 2>
The following undercoat layer, charge generation layer, charge transport layer, and surface protective layer were formed on the same endless belt-like substrate as in Example 1 in the same manner as in Example 1.

[Formation of undercoat layer]
A mixture (γ-amino) of 170 parts by mass of n-butyl alcohol, 30 parts by mass of an organic zirconium compound (acetylacetone zirconium butyrate) in which 4 parts by mass of polyvinyl butyral resin (Surek BM-S manufactured by Sekisui Chemical Co., Ltd.) was dissolved 3 parts by mass of (propyltrimethoxysilane) was further mixed and stirred to obtain a coating solution for an undercoat layer. An undercoat layer was applied to the surface of the endless belt-like substrate using a dip coating apparatus, and a curing treatment at 150 ° C. for 1 hour was performed to form an undercoat layer having a thickness of 1.0 μm.

[Formation of charge generation layer]
Next, at least at 7.5 °, 9.9 °, 12.5 °, 16.3 ° in the Bragg angle (2θ ± 0.2 °) of the X-ray diffraction spectrum using Cukα rays as the charge generation material. , 18.6 °, 25.1 °, 28.1 °, 15 parts by mass of hydroxygallium phthalocyanine from which a clear diffraction peak is obtained, butyral resin (BM-1, manufactured by Sekisui Chemical Co., Ltd.) 10 as a binder resin A mixture composed of part by mass and 300 parts by mass of n-butyl alcohol was dispersed in a sand mill for 4 hours. The obtained dispersion was used as a coating solution for the charge generation layer, which was dip-coated on the surface of the undercoat layer and dried to form a charge generation layer having a thickness of 0.2 μm.

[Formation of charge transport layer]
Next, 2 parts by mass of di (3,4-dimethylphenyl) (4-phenylphenyl) amine and N, N′-diphenyl-N, N′-bis (3-methylphenyl)-[1,1′-biphenyl ] -4,4'-diamine 2 parts by mass and bisphenol Z polycarbonate (viscosity average molecular weight 40,000) 6 parts by mass, tetrahydrofuran 80 parts by mass, 2,6-di-t-butyl-4-methylphenol 0.2 A part by mass was added and dissolved. The obtained liquid was applied as a charge transport layer coating solution by dip coating on the surface of the charge generation layer and dried at 120 ° C. for 40 minutes to form a charge transport layer having a thickness of 25 μm.

[Formation of surface protective layer]
Then, 2 parts by mass of the compound shown below, 2 parts by mass of methyltrimethoxysilane, 1 part by mass of tetramethoxysilane, 0.3 part by mass of colloidal silica, 5 parts by mass of isopropyl alcohol, 3 parts by mass of tetrahydrofuran, 3 parts by mass of distilled water After adding the ion exchange resin (0.5 parts by mass) and hydrolyzing at room temperature for 24 hours, the ion exchange resin was separated by filtration, 0.1 parts by mass of aluminum trisacetylacetonate, 3,5-t -0.4 part by mass of butyl-4-hydroxytoluene (BHT) was added to prepare a coating solution. This coating solution was dip-coated on the surface of the charge transport layer and dried at 150 ° C. for 1 hour to obtain a surface protective layer having a thickness of 3 μm.
As a result, an intermediate transfer member of the present invention having the layer structure shown in FIG. 2B was obtained.

The surface microhardness on the surface layer side of the intermediate transfer member in Example 2 was measured in the same manner as in Example 1, and was 30 degrees.
Further, the volume resistivity of the intermediate transfer member in Example 2 in a state where the intermediate transfer member was not irradiated with light was measured by the same method as the measurement method of the substrate in Example 1, and found to be 1 × 10 ^14.0 Ωcm.

<Example 3>
A photoconductive layer having a single layer structure was formed on an endless belt-like base material as in Example 1 as follows.

[Formation of single-layer photoconductive layer]
At least 7.5 °, 9 in the Bragg angle (2θ ± 0.2 °) of the X-ray diffraction spectrum using the Cukα ray as the charge generation material with respect to 100 parts by mass of the bisphenol A type polycarbonate as the binder resin. 15 parts by mass of hydroxygallium phthalocyanine capable of obtaining clear diffraction peaks at positions of .9 °, 12.5 °, 16.3 °, 18.6 °, 25.1 °, 28.1 °, and a charge transport material 100 parts by mass of the specific hydrazone compound represented by the following structural formula and 900 parts by mass of tetrahydrofuran were mixed and dispersed in a sand mill for 4 hours. The obtained dispersion was used as a coating liquid for the photoconductive layer. This coating solution was applied to the surface of an endless belt-like substrate by a dip coating method and dried at 90 ° C. for 1 hour to form a photoconductive layer having a thickness of 25 μm.
As a result, an intermediate transfer member of the present invention having the layer structure shown in FIG. 1 was obtained.

The surface microhardness on the surface layer side of the intermediate transfer member in Example 3 was measured in the same manner as in Example 1, and was 20 degrees.
Further, the volume resistivity of the intermediate transfer member in Example 3 in a state where the intermediate transfer member was not irradiated with light was measured by the same method as that for measuring the substrate in Example 1, and found to be 1 × 10 ^14.0 Ωcm.

<Example 4>
In Example 3, a single-layer photoconductive layer was formed in the same manner as in Example 3 except that a specific hydrazone compound having the following structural formula was used as the charge transport material and the film thickness was 50 μm.
As a result, an intermediate transfer member of the present invention having the layer structure shown in FIG. 1 was obtained.

The surface microhardness on the surface layer side of the intermediate transfer member in Example 4 was measured in the same manner as in Example 1 and found to be 21 degrees.
Further, the volume resistivity of the intermediate transfer member in Example 4 in a state where the intermediate transfer member was not irradiated with light was measured by the same method as that for measuring the substrate in Example 1, and found to be 1 × 10 ^14.0 Ωcm.

<Example 5>
[Preparation of belt-shaped substrate]
100 parts by mass of vinylidene fluoride-hexafluoropropylene copolymer (made by Kureha Chemical Industry Co., Ltd .: trade name “# 2300”) as a resin material of the base material, oxidized carbon black (trade name: purine) as a conductive agent 15 parts by weight of Tex 140U (pH 4.5%: manufactured by Degussa Japan) was added and dispersed and kneaded with a twin screw extruder to obtain a resin composition. This was molded into an endless belt shape having a thickness of 0.12 mm using a single screw extruder to obtain a substrate.
The obtained base material had a Young's modulus of 1,500 MPa, a volume resistivity of 5 × 10 ¹⁰ Ωcm, and a surface resistivity of 1 × 10 ¹¹ Ω / □.

On the obtained base material, an undercoat layer, a charge generation layer, and a charge transport layer similar to those in Example 1 are formed, and the intermediate transfer member of the present invention having the layer structure shown in FIG. Obtained.
The surface microhardness on the surface layer side of the intermediate transfer member in Example 5 was measured in the same manner as in Example 1 and was 21 degrees.
Further, the volume resistivity of the intermediate transfer member in Example 5 in a state where the intermediate transfer member was not irradiated with light was measured by the same method as the measurement method of the substrate in Example 1, and found to be 9 × 10 ¹³ Ωcm.

<Example 6>
[Preparation of belt-shaped substrate]
100 parts by mass of polyvinylidene fluoride resin (made by Kureha Chemical Industry Co., Ltd .: trade name “# 850”) as a resin material of the base material, oxidized carbon black (trade name: Printex 140U (pH 4.5) as a conductive agent) %): Degussa Japan Co., Ltd.) 16 parts by weight was added and dispersed and kneaded with a twin screw extruder to obtain a resin composition. This was molded into an endless belt with a thickness of 0.12 mm using a single screw extruder to obtain a substrate.
The obtained base material had a Young's modulus of 1,900 MPa, a volume resistivity of 1 × 10 ¹⁰ Ωcm, and a surface resistivity of 8 × 10 ¹⁰ Ω / □.

An undercoat layer, a charge generation layer, a charge transport layer, and a surface protective layer similar to those of Example 2 are formed on the obtained substrate, and the layer structure shown in FIG. An intermediate transfer member was obtained.
The surface microhardness on the surface layer side of the intermediate transfer member in Example 6 was 30 degrees as measured in the same manner as in Example 1.
Further, the volume resistivity of the intermediate transfer member in Example 6 in a state where the intermediate transfer member was not irradiated with light was measured by the same method as the measurement method of the substrate in Example 1, and found to be 8 × 10 ¹³ Ωcm.

<Example 7>
Example 5 is the same as Example 5 except that 5 parts by mass of fluorine resin particles (Teflon (registered trademark) particles having a volume average particle diameter of 0.3 μm: manufactured by Mitsui DuPont Fluorochemical Co., Ltd.) are added to the charge transport layer in Example 5. Similarly, an intermediate transfer member of the present invention having the layer structure shown in FIG. 2 (A) was obtained.
The surface microhardness on the surface layer side of the intermediate transfer member in Example 7 was 18 degrees as measured in the same manner as in Example 1.
Further, the volume resistivity of the intermediate transfer member in Example 7 in a state where the intermediate transfer member was not irradiated with light was measured by the same method as the measurement method of the substrate in Example 1, and found to be 3 × 10 ¹⁴ Ωcm. The surface resistivity was 3 × 10 ¹⁴ Ω / □.

<Example 8>
[Preparation of belt-shaped substrate]
To 100 parts by mass of polypropylene (Idemitsu Kosan Co., Ltd. RB110 (trade name)) as a resin material for the base material, 15 parts by mass of Ketchen Black as a conductive agent is added, and dispersed and kneaded with a twin screw extruder. A pellet of the resin composition was obtained. Next, the pellet was molded into an endless belt shape having a thickness of 0.15 mm using a single screw extruder to obtain a base material.
The obtained base material had a Young's modulus of 950 Mpa, a volume resistivity of 5 × 10 ¹⁰ Ωcm, and a surface resistivity of 1 × 10 ¹¹ Ω / □.

On the obtained base material, an undercoat layer, a charge generation layer, and a charge transport layer similar to those in Example 1 are formed, and the intermediate transfer member of the present invention having the layer structure shown in FIG. Obtained.
The surface microhardness on the surface layer side of the intermediate transfer member in Example 8 was measured in the same manner as in Example 1 and was 21 degrees.
Further, the volume resistivity of the intermediate transfer member in Example 8 in a state where the intermediate transfer member was not irradiated with light was measured by the same method as the measurement method of the substrate in Example 1, and found to be 8 × 10 ¹³ Ωcm.

<Comparative Example 1>
The polyamic acid solution containing carbon black (A) in Example 1 was applied to the inner surface of the cylindrical mold so that the thickness of the coating film became 0.5 mm via a dispenser, and the mold was rotated at 1500 rpm for 15 minutes. After forming a coating film having a uniform thickness, hot air of 60 ° C. was applied for 30 minutes from the outside of the mold while rotating the mold at 250 rpm, and then heated at 150 ° C. for 60 minutes and cooled to room temperature. A film was formed.
Thereafter, the film formed on the inner surface of the mold is peeled off, and this film is coated so as to cover the outer periphery of the metal core, and the temperature is increased to 400 ° C. at a rate of 2 ° C./min. For 30 minutes to remove the solvent and dehydrated ring-closing water remaining in the film and complete the imide conversion reaction. Thereafter, after cooling the metal core to room temperature, the polyimide film formed on the surface of the metal core was peeled off to obtain an endless belt having a thickness of 0.08 mm.
The resulting endless belt had a Young's modulus of 3,800 Mpa, a volume resistivity of 1 × 10 ^9.5 Ωcm, and a surface resistivity of 1 × 10 ¹² Ω / □.
The obtained endless belt made of polyimide resin was used as an intermediate transfer member.
Here, when the surface microhardness of the intermediate transfer member in Comparative Example 1 was measured in the same manner as in Example 1, it was 28 degrees.

<Comparative example 2>
An intermediate transfer member having the layer structure shown in FIG. 2A was obtained in the same manner as in Example 1 except that an endless belt-like substrate as shown below was used.

(Preparation of polyamic acid solution (B))
N-methyl-2-pyrrolidone (NMP) solution of polyamic acid composed of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) and 4,4′-diaminodiphenyl ether (DDE) (manufactured by Ube Industries) For Euvarnish S (solid content 18% by mass), 100 parts by mass of the solid content of the raw material capable of forming the polyimide resin in this solution, dry oxidized carbon black (SPECIAL BLACK4 (manufactured by Degussa, pH 3.0, volatile content: 14.0%) was added to 7 parts by mass, and after using a collision type disperser (GeanusPY made by Seanas), the pressure was 200 MPa, and the minimum area was 1.4 mm ² It was made to collide, and the path | route which divides into 2 again was passed 5 times, and it mixed, and obtained the polyamic-acid solution (B) containing carbon black for base materials.

(Formation of base material)
The polyamic acid solution (B) containing carbon black is applied to the inner surface of the cylindrical mold so that the thickness of the coating film becomes 0.5 mm via a dispenser, and the mold is rotated at 1500 rpm for 15 minutes to obtain a uniform thickness. After forming the coating film having a temperature of 60 ° C from the outside of the mold for 30 minutes while rotating the mold at 250 rpm, the coating film was heated to 150 ° C for 60 minutes and cooled to room temperature. Formed.
Thereafter, the film formed on the inner surface of the mold is peeled off, and this film is coated so as to cover the outer periphery of the metal core, and the temperature is increased to 400 ° C. at a rate of 2 ° C./min. For 30 minutes to remove the solvent and dehydrated ring-closing water remaining in the film and complete the imide conversion reaction. Thereafter, after cooling the metal core to room temperature, the polyimide film formed on the surface of the metal core was peeled off to obtain an endless belt-like base material having a thickness of 0.08 mm.
The obtained base material had a Young's modulus of 3,700 MPa, a volume resistivity of 1 × 10 ^12.0 Ωcm, and a surface resistivity of 1 × 10 ¹⁴ Ω / □.
The obtained endless belt made of polyimide resin was used as an intermediate transfer member.
Here, when the surface microhardness of the intermediate transfer member in Comparative Example 2 was measured in the same manner as in Example 1, it was 27 degrees.

<Comparative Example 3>
An intermediate transfer member having the layer structure shown in FIG. 2A was obtained in the same manner as in Example 5 except that an endless belt-like substrate as shown below was used.

(Preparation of polyamic acid solution (C))
N-methyl-2-pyrrolidone (NMP) solution of polyamic acid composed of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) and 4,4′-diaminodiphenyl ether (DDE) (manufactured by Ube Industries) For Euvarnish S (solid content 18% by mass), 100 parts by mass of the solid content of the raw material capable of forming the polyimide resin in this solution, dry oxidized carbon black (SPECIAL BLACK4 (manufactured by Degussa, pH 3.0, volatile content: 14.0%) was added to 25 parts by mass, and after using a collision type disperser (GeanusPY made by Seanas), the pressure was 200 MPa, and the minimum area was 1.4 mm ² It was made to collide, and the path | route which divides into 2 again was passed 5 times, and it mixed, and obtained the polyamic-acid solution (C) containing carbon black for base materials.

(Formation of base material)
The polyamic acid solution (C) containing carbon black is applied to the inner surface of the cylindrical mold so that the thickness of the coating film becomes 0.5 mm via a dispenser, and the mold is rotated at 1500 rpm for 15 minutes to obtain a uniform thickness. After forming a coating film having a temperature of 60 ° C. from the outside of the mold for 30 minutes while rotating the mold at 250 rpm, the coating film was heated to 150 ° C. for 60 minutes and cooled to room temperature. Formed.
Thereafter, the film formed on the inner surface of the mold is peeled off, and this film is coated so as to cover the outer periphery of the metal core, and the temperature is increased to 400 ° C. at a rate of 2 ° C./min. For 30 minutes to remove the solvent and dehydrated ring-closing water remaining in the film and complete the imide conversion reaction. Thereafter, after cooling the metal core to room temperature, the polyimide film formed on the surface of the metal core was peeled off to obtain an endless belt-like base material having a thickness of 0.08 mm.
The obtained substrate had a Young's modulus of 3,800 Mpa, a volume resistivity of 1 × 10 ^9.2 Ωcm, and a surface resistivity of 5 × 10 ¹¹ Ω / □.
The obtained endless belt made of polyimide resin was used as an intermediate transfer member.
Here, when the surface microhardness of the intermediate transfer member in Comparative Example 3 was measured in the same manner as in Example 1, it was 28 degrees.

<Evaluation of transfer image quality>
The obtained intermediate transfer member is mounted as an intermediate transfer belt 22 on a Fuji Xerox Co., Ltd. Docu Color 1255CP having substantially the same configuration as the image forming apparatus shown in FIG. The lamp 91 and the charge removal conductive member 90 were also mounted as shown in FIG. Here, as the static elimination lamp 91, red light LED (wavelength 720nm) was used. As the charge removal conductive member 90, a carbon black-dispersed epichlorohydrin rubber roll was used by dispersing a conductive agent having a volume resistance adjusted to 10 ⁶ Ω.
Using such an image forming apparatus, transfer image quality by secondary transfer was evaluated. The recording paper 61 used here is Fuji Xerox Office Supply Co., Ltd. full color copier paper J paper.
As the toner, a spherical toner having a shape factor (SF) of 125 and a volume average particle diameter of 5.5 μm was used.
The print sample is configured as an image pattern, and the first sheet is composed of a solid color of 2 cm square of yellow, magenta, cyan, and black, a secondary color, and a tertiary color, and a line image.

(Evaluation results)
In Examples 1 to 8, uniform images without density unevenness and blur (toner scattering) were obtained in the first print sample. Here, immediately after the secondary transfer, the surface potential of the intermediate transfer belt 22 in each of Examples 1 to 8 had surface potential unevenness that seems to correspond to an image pattern of about −300V to −400V. When the charge removal by the charge removal conductive member 90 is performed after the discharge lamp 91 is turned on, the surface potential of the intermediate transfer belt 22 becomes substantially uniform between -10V and -30V.
Subsequently, even in the second print sample, a uniform image free from density unevenness and blur (toner scattering) was obtained. Similarly, although 10,000 sheets were output continuously, a good image free from density unevenness and blur (toner scattering) was obtained.
In Example 8, since the Young's modulus of the substrate was as small as 950 MPa, there was no significant problem with the transfer image quality, but a slight color registration shift occurred.

  In Comparative Examples 1 and 3, the surface potential of the intermediate transfer belt 22 is almost uniform between 10 V and −30 V immediately after the second transfer of the first print sample. Since the volume resistance value of the belt was low and the charge holding force on the belt surface after the primary transfer was weak, blur was generated and the image quality was at a problem level.

  In Comparative Example 2, a uniform image without density unevenness and blur (toner scattering) was obtained in the first print sample. However, immediately after the secondary transfer, the surface potential of the intermediate transfer belt 22 has surface potential unevenness that seems to correspond to an image pattern of about −300 V to −400 V, and density unevenness occurs in the second print sample. However, continuous image quality evaluation was not possible.

FIG. 3 is a schematic cross-sectional view illustrating a configuration example of an intermediate transfer member of the present invention. FIG. 2 is a schematic cross-sectional view illustrating a configuration example of an intermediate transfer member of the present invention, (A) is a schematic cross-sectional view illustrating a configuration of an intermediate transfer member 100a of the present invention, and (B) is a diagram of an intermediate transfer member 100b of the present invention. It is a schematic sectional drawing which shows a structure. It is the schematic plan view (A) and schematic sectional drawing (B) which show an example of a circular electrode. It is a schematic diagram which shows the measurement principle of the surface micro hardness on the surface layer side. FIG. 3 is a schematic diagram for explaining a main part of the image forming apparatus of the present invention. It is a schematic diagram showing another example of the image forming apparatus of the present invention. It is explanatory drawing of the technique of Unexamined-Japanese-Patent No. 7-146616 which is patent document 11. FIG. It is explanatory drawing of the technique of Unexamined-Japanese-Patent No. 7-146616 which is patent document 11. FIG. It is explanatory drawing of the technique of Unexamined-Japanese-Patent No. 5-257398 which is the patent document 12. FIG. It is explanatory drawing of the problem which arises when transferring the developed image of the 2nd color by the technique of Unexamined-Japanese-Patent No. 5-257398 which is patent document 12. FIG. It is explanatory drawing of the technique which transfers by light irradiation using the intermediate transfer body which resistance value falls by light irradiation of Unexamined-Japanese-Patent No. 6-282181 which is patent document 13. FIG. It is explanatory drawing of the technique which transfers by application of pressurization using the intermediate transfer body which resistance value falls by the pressurization of Unexamined-Japanese-Patent No. 6-282181 which is patent document 13. FIG.

Explanation of symbols

01 Blanket (intermediate transfer member)
02 Photosensitive drum 1 Intermediate transfer member 10 Needle-shaped indenter 12 Surface layer 21 on the surface layer side Photosensitive drum (image carrier)
22 Intermediate transfer belt (intermediate transfer member)
23 Bias roller (second transfer means)
24 Paper tray 25 Black developing device 26 Yellow developing device 27 Magenta developing device 28 Cyan developing device 29 Intermediate transfer body cleaner 33 Peeling claw 41 Belt roller 42 Backup roller 43 Belt roller 44 Belt roller 45 Conductive roller (first transfer means)
46 Electrode roller 50 Static elimination roll 51 Cleaning blade 61 Recording paper 62 Pickup roller 63 Feed roller 71 Toner cartridge 72 Fixing roll 73 Backup roll 74 Tension roll 75 Secondary transfer roll 76 Paper path 77 Paper tray 78 Laser generator 79 Photoconductor 80 1 Next transfer roll 81 Drive roll 82 Transfer cleaner 83 Charging roll 84 Photoconductor cleaner 85 Developer 86 Intermediate transfer belt (intermediate transfer body)
90 Electroconductive member 91 for static elimination Electrostatic discharge lamp 100a, 100b Intermediate transfer body 110 Base material 120 Surface layer 121 Single-layer photoconductive layer 122 Undercoat layer 124 Charge generation layer 126 Charge transport layer 128 Surface protective layer T Toner image Q1 Primary Transfer area Q2 Secondary transfer area Q3 Primary transfer area Q4 Secondary transfer area Q5 Static elimination area

Claims (9)

An intermediate transfer body having a base material and a surface layer provided on the base material,
An intermediate transfer member, wherein the surface layer is a photoconductive layer.   The intermediate transfer member according to claim 1, wherein the photoconductive layer contains a charge transport material, a charge generation material, and a binder resin. An intermediate transfer body having a base material and a surface layer provided on the base material,
The intermediate transfer member, wherein the surface layer is a photoconductive layer having a charge transport layer and a charge generation layer provided on the substrate side of the charge transport layer.   The intermediate transfer member according to any one of claims 1 to 3, wherein the substrate is composed of a thermosetting resin or a thermoplastic resin, and has a Young's modulus of 1,000 Mpa or more. . 5. The intermediate transfer member according to claim 1, wherein the substrate has a volume resistivity of 1 × 10 ⁶ to 1 × 10 ¹³ Ωcm.   The intermediate transfer member according to claim 5, wherein the base material is composed of a polyimide resin obtained by dispersing a conductive agent.   The intermediate transfer member according to any one of claims 1 to 6, wherein the surface layer contains fluorine-based resin particles.   The intermediate transfer member according to any one of claims 1 to 7 and the toner image formed on the surface of the intermediate transfer member are transferred to a transfer material, and then the surface of the intermediate transfer member is irradiated with light. An image forming apparatus comprising: an optical charge eliminating unit for removing charge. The image forming apparatus according to claim 8, wherein a spherical toner having a shape factor (SF) defined by the following formula (1) of the toner of 140 to 100 is used.
Formula (1)
(SF) = [(absolute maximum length of toner particles) ² × π × 100] / [(projection area of toner particles) × 4]

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