JP6221741B2 - Intermediate transfer body, tubular body unit, image forming apparatus, and process cartridge - Google Patents

Description

The present invention relates to an intermediate transfer body, a tubular body unit , an image forming apparatus, and a process cartridge.

  Patent Document 1 discloses a conductive endless material comprising a resin composition containing a thermoplastic resin, an electronic conductive agent and an ionic conductive agent, and a volume resistance value and a surface resistance value satisfy a specific relationship. A belt is disclosed.

  Patent Document 2 discloses an intermediate transfer member in which a thermoplastic resin containing polyphenylene sulfide as a main component is extruded by an annular die of an extruder.

  In Patent Document 3, a molding raw material is melt-extruded into a cylindrical shape with an extruder, molded into a desired shape and dimension, contains a thermoplastic resin and an ion conductive resistance control agent, and is extruded from the tip of an annular die. An intermediate transfer member is disclosed which is obtained by discharging a cylindrical melt by extrusion and having a diameter having a specific ratio with respect to the die diameter of the annular die.

JP 2007-328171 A JP 2000-275984 A JP 2000-275980 A

  An object of the present invention is to provide a tubular body having a small variation in surface resistivity.

The above problem is solved by the following means. That is,
The invention according to claim 1
A crystalline resin;
Carbon black,
0.5 to 5 parts by mass of nigrosine dye with respect to 100 parts by mass of the crystalline resin,
Is an intermediate transfer member .

The invention according to claim 2
The intermediate transfer member according to claim 1, wherein the crystalline resin is a polyphenylene sulfide resin.

The invention according to claim 3
3. The intermediate transfer member according to claim 1, wherein an average primary particle size of the carbon black is 25 nm or less.

The invention according to claim 4
A tubular body constituting the intermediate transfer body according to any one of claims 1 to 3, and a plurality of rolls that span the tubular body in a tensioned state, and is attached to and detached from the image forming apparatus A tubular body unit.

The invention according to claim 5,

An image carrier,
Charging means for charging the surface of the image carrier;
Latent image forming means for forming a latent image on the surface of the charged image carrier;
Developing means for developing a latent image on the surface of the image carrier with toner to form a toner image;
The intermediate transfer member according to any one of claims 1 to 3 , wherein the toner image formed on a surface of the image carrier is transferred.
Primary transfer means for primarily transferring the toner image formed on the surface of the image carrier to the surface of the intermediate transfer member;
Secondary transfer means for secondary transfer of the toner image transferred to the surface of the intermediate transfer body to a recording medium;
An image forming apparatus.

The invention according to claim 6
The intermediate transfer member according to any one of claims 1 to 3 ,
An image carrier, a charging unit for charging the surface of the image carrier, a latent image forming unit for forming a latent image on the charged surface of the image carrier, and developing a latent image on the surface of the image carrier with toner. Development means for forming a toner image, primary transfer means for primary transfer of the toner image formed on the surface of the image holding member to the surface of the intermediate transfer member, and the toner image transferred to the surface of the intermediate transfer member. Secondary transfer means for secondary transfer to the recording medium, cleaning means for cleaning the surface of the intermediate transfer body after the toner image is secondarily transferred, and fixing for fixing the toner image transferred to the recording medium At least one selected from means;
And a process cartridge that is detachable from the image forming apparatus.

According to the first aspect of the present invention, it is possible to provide an intermediate transfer body comprising a tubular body having a small variation in surface resistivity as compared with a case where the content of nigrosine dye is less than the above range.

According to the invention of claim 2, compared with the case the content of nigrosine dye is less than the above range, even if the crystalline resin is a polyphenylene sulfide resin, the surface resistivity of the variation is small tubular body An intermediate transfer member can be provided.

According to the invention of claim 3, compared to when the content of nigrosine dye is less than the above range, even an average primary particle diameter of the range of carbon black, from the variation of the surface resistivity is less tubular body An intermediate transfer member can be provided.

  According to the invention which concerns on Claim 4, compared with the tubular body unit provided with the tubular body in which content of nigrosine dye is less than the said range, a tubular body unit provided with the tubular body with a small variation in surface resistivity can be provided. .

According to the invention of claim 5 ,

An image forming apparatus capable of forming an image in which unevenness of image density due to variation in surface resistivity in a tubular body is suppressed as an intermediate transfer body compared to a case where a tubular body having a nigrosine dye content less than the above range is provided. Can be provided.

According to the invention of claim 6 , as compared with the case where the intermediate transfer body is provided with a tubular body in which the content of nigrosine dye is less than the above range, image density unevenness due to variation in surface resistivity in the tubular body is suppressed. A process cartridge can be provided on which the processed image is formed.

It is a schematic perspective view which shows the tubular body unit which concerns on this embodiment. 1 is a schematic configuration diagram illustrating an image forming apparatus according to an exemplary embodiment.

  Hereinafter, embodiments of the present invention will be described in detail.

[Tubular body]
The tubular body according to this embodiment contains a crystalline resin, carbon black, and nigrosine dye in an amount of 0.5 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the crystalline resin.
Since the tubular body according to the present embodiment has the above configuration, the variation in surface resistivity is small as compared with the case where the content of nigrosine dye is less than the above range or the case where no nigrosine dye is included.

  A tubular body in which carbon black is dispersed in a crystalline resin can be obtained, for example, by extruding a tubular resin in which carbon black is dispersed in a crystalline resin melted at a temperature of 280 ° C. or higher. In particular, since the tubular body obtained by the above method tends to cause variations in film thickness, it has been considered that the variation in film thickness is a cause of variations in surface resistivity.

On the other hand, in the present embodiment, a tubular body having a small variation in surface resistivity can be obtained by including a specific amount of nigrosine dye in addition to the crystalline resin and carbon black even if there is a variation in film thickness. It was.
Nigrosine dyes are known to have a crystallization delay effect. Conventional nigrosine dyes are also used as charge control agents in developers. However, in the present embodiment, it has been found that the above-mentioned effect can be obtained only by using a large amount (amount in the above range) of nigrosine dye as compared with the case of using nigrosine dye as a crystallization retarder or the charge control agent. It was.

  In particular, when a polyphenylene sulfide resin is used as a crystalline resin, carbon black is less likely to disperse than when other resins are used, and the conventional tubular body has a variation in surface resistivity due to the uneven distribution of carbon black. Arise. However, in this embodiment, since a specific amount of nigrosine dye is included, even in a form using a polyphenylene sulfide resin, the variation in surface resistivity in the tubular body is small compared to the case where the specific amount of nigrosine dye is not included.

  Also, when carbon black having an average primary particle size in the above range is used, carbon black is less likely to be dispersed than when carbon black having an average primary particle size larger than the above range is used. However, similarly to the above, since the specific amount of nigrosine dye is included in the present embodiment, the surface resistance in the tubular body is also increased in the form using carbon black having a small average primary particle size compared to the case where the specific amount of nigrosine dye is not included. The rate variation is small.

  Then, by performing image formation using the tubular body of the present embodiment as an intermediate transfer body, image density unevenness due to variation in surface resistivity in the tubular body is suppressed as compared to the case of using a conventional tubular body. An image is formed. In particular, by using a tubular body having a variation in surface resistivity of 0.3 log Ω / □ or less as an intermediate transfer body, a high quality image with less density unevenness can be obtained compared to a tubular body having a large variation in surface resistivity. An image is formed.

If the content of nigrosine dye is too large (more than the above range), the average surface resistivity of the tubular body tends to increase, and if a large amount of carbon black is added to lower the average surface resistivity of the tubular body, the tubular body The strength of the body is reduced.
On the other hand, in this embodiment, since the content of nigrosine dye is in the above range, even if the addition amount of carbon black is suppressed to such an extent that the strength of the tubular body is maintained, the content of nigrosine dye is more than the above range. Compared with the case where there are many, it is easy to adjust the average surface resistivity of a tubular body as aimed. For this reason, in the present embodiment, a tubular body with a small variation in surface resistivity is obtained while ensuring high strength and a target average surface resistivity, and density unevenness is suppressed by forming an image using the tubular body. Images are obtained.

  Moreover, in this embodiment, since content of nigrosine dye is the said range, compared with the case where it is more than the said range, it is easy to adjust the average surface resistivity of a tubular body.

  The nigrosine dye content is preferably 0.5 parts by mass or more and 5.0 parts by mass or less, and more preferably 1.0 part by mass or more and 4.0 parts by mass or less with respect to 100 parts by mass of the crystalline resin.

  Next, constituent materials constituting the tubular body according to the present embodiment, characteristics of the tubular body, and the like will be described.

  The tubular body according to this embodiment contains at least a crystalline resin, carbon black, and nigrosine dye, and may contain other additives. Moreover, the tubular body should just have the layer containing crystalline resin, carbon black, and nigrosine dye, and the laminated body which laminated | stacked this layer and the other layer may be sufficient as it.

-Crystalline resin-
The crystalline resin refers to a resin having a clear endothermic peak instead of a stepwise endothermic amount change in differential scanning calorimetry (DSC).
Specifically, for example, a crystalline resin means that the half-value width of an endothermic peak when measured at a heating rate of 10 ° C./min is within 10 ° C., and an amorphous resin means an endothermic peak. It means a resin in which a stepwise endothermic change that is a glass transition point can be recognized.

The crystalline resin is not particularly limited, and a general thermoplastic resin used for a tubular body can be used. For example, polyphenylene sulfide resin (PPS), polyamide resin (PA), polyetherimide resin (PEI), polyetheretherketone resin (PEEK), polyethersulfone (PES), polyphenylsulfone (PPSU), polysulfone ( PSF), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polaracetal resin (POM), polycarbonate (PC) and the like. Among them, preferred crystalline resins from the viewpoint of balance between strength and moldability include polyphenylene sulfide resin (PPS) and polyethylene terephthalate, and in addition, polyphenylene sulfide resin (PPS) is more preferable from the viewpoint of flame retardancy.
Further, as the crystalline resin, only one of the above may be used, or two or more may be used in combination.

  In addition, examples of the crystalline resin used when the tubular body is obtained by extrusion molding include thermoplastic resins having a melting temperature of 100 ° C. or higher, preferably 350 ° C. or lower, more preferably 300 ° C. or lower. This is from the viewpoint of reducing the influence of foreign matters caused by resin decomposition during processing.

The melting temperature represents a temperature at which the viscosity of the crystalline resin becomes 10,000 Pa · s or less, and is measured by the following method.
That is, the melting temperature is measured by a capillary rheometer at the heating temperature when the melt viscosity is measured by detecting the shear rate and shear stress when the molten resin flows out through the capillary.

・ Polyphenylene sulfide resin (PPS)
Examples of the polyphenylene sulfide resin include the following formula (1) obtained by a method of polymerizing dichlorobenzene and sodium sulfide as monomers, that is, a Philips Petroleum method which is a general synthesis method of a polyphenylene sulfide resin. And a polymer containing a repeating structural unit.

Uncrosslinked polyphenylene sulfide resin is a resin having a one-dimensional molecular chain that is not crosslinked, and is excellent in toughness and stretchability.
Further, a resin having a cross-linked structure may be used as the polyphenylene sulfide resin. Specifically, for example, a single bond is present in the same molecular chain or between different molecular chains, and in the same molecular chain and between different molecular chains. And a crosslinked structure of a polyphenylene sulfide resin crosslinked through an ether bond. For example, those having a cross-linked structure of polyphenylene sulfide resin cross-linked with an ether bond (structure of the following formula (2)) and a cross-linked structure of polyphenylene sulfide resin cross-linked with a single bond (structure of the following formula (3)) are included. .

  Examples of the commercially available polyphenylene sulfide resin include T1881-3 manufactured by Toray Industries, Inc., FZ2100 manufactured by DIC, and Fortron 0220A manufactured by Polyplastics.

-Nigrosine dye-
Nigrosine dye is, for example, an azine-based compound obtained by adding hydrochloric acid to aniline or a mixture of aniline hydrochloride and nitrobenzene, and dehydrating, deammonising, and oxidizing / reducing condensation reaction under a catalyst such as copper or iron. In general, it is a mixture of compounds having an azine skeleton.
Specific examples of commercially available nigrosine dyes include, for example, SOM-L-0468, nigrosine base EX, nigrosine base EE, special black EB, oil black BY, oil black no. 5 (above, manufactured by Orient Chemical Co., Ltd.), Oil Black S, Oil Black FS Special (above, manufactured by Chuo Synthetic Chemical Co., Ltd.), Nigrosine Base LK (manufactured by BASF), SOT Black-12H, SOT Black-13 Liquid (Hodogaya) Chemical Industry Co., Ltd.).
Among them, preferred nigrosine dyes include, for example, SOM-L-0468 from the viewpoint of heat resistance.

-Carbon black-
The carbon black is not particularly limited. For example, ketjen black, oil furnace black, channel black, acetylene black, surface oxidized carbon black (surface oxidized carbon black), graphitized carbon with surface graphitized Black etc. are mentioned. As carbon black, only one of these may be used, or two or more may be used in combination.
The surface-oxidized carbon black is obtained by imparting, for example, a carboxyl group, a quinone group, a lactone group, a hydroxyl group or the like to the surface. Examples of the surface oxidation treatment include an air oxidation method in which a reaction is caused by contact with air in a high temperature atmosphere, a method of reacting with nitrogen oxide or ozone at a normal temperature (for example, 22 ° C.), and air in a high temperature atmosphere. Examples include a method of oxidizing with ozone at a low temperature after oxidation.

The average primary particle size of carbon black is preferably 25 nm or less, more preferably 13 nm or more and 25 nm or less, and further preferably 13 nm or more and 20 nm or less.
Compared to the case where the average primary particle size is less than the lower limit, it is easier to obtain good dispersibility of the carbon black when the average primary particle size is in the above range. As a result, the appearance of the formed intermediate transfer belt is improved, and image defects due to defects are less likely to occur.
Then, compared to the case where the average primary particle size is larger than the above upper limit value, the case where the average primary particle size is in the above range is used for an aspect in which the discharge is repeatedly generated like the intermediate transfer belt in the image forming apparatus. Even in such a case, it is easy to obtain an effect that the decrease in surface resistivity due to repeated discharge is less likely to occur.

  The average primary particle size of carbon black is measured by the following method. First, the tubular body is cut with a microtome to obtain a measurement sample having a thickness of 100 nm, and the measurement sample is observed with a TEM (transmission electron microscope). The diameter of a circle equal to the projected area of each of the 50 carbon black particles is defined as the particle diameter, and the average value is defined as the average primary particle diameter.

The blending amount of the carbon black may be set to an amount capable of obtaining the conductivity of the target tubular body. For example, the amount is 8 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the crystalline resin. More preferred is 25 parts by mass or less.
Compared with the case where the blending amount of the carbon black is less than the lower limit, the resistivity within the tubular body is less likely to decrease with time when the amount is within the above range. On the other hand, compared to the case where the upper limit value is exceeded, breakage and end tears due to the brittleness of the tubular body are less likely to occur within the above range.

  Moreover, you may use together other electrically conductive agents other than carbon black with the tubular body concerning this embodiment. However, the proportion of carbon black in the contained conductive agent is preferably 80% by mass or more, and more preferably contains only carbon black as the conductive agent.

Other conductive agents include, for example, metals such as aluminum and nickel; metal oxides such as yttrium oxide and tin oxide; ion conductive materials such as potassium titanate and potassium chloride; and high conductivity such as polyaniline, polypyrrole, and polyacetylene. Molecule and the like.
In addition, a electrically conductive agent points out the substance which can provide the electroconductivity made into the tubular body which concerns on this embodiment by adding.

-Other additives-
As other additives, for example, an antioxidant for preventing thermal deterioration of the tubular body, a surfactant for improving fluidity, a heat resistant anti-aging agent, etc., particularly blended in an endless belt of an image forming apparatus. And known additives.

-Physical properties-
Next, the physical properties of the tubular body according to this embodiment will be described.
The tubular body according to this embodiment has a surface resistivity (average surface resistivity of the tubular body) of 7 logΩ / measured when measured by applying a voltage of 100 V in a normal temperature and normal humidity (temperature 22 ° C., humidity 55 RH%) environment. □ or more and 13Ω / □ or less, especially when a tubular body is applied as an intermediate transfer belt, it is preferably 8 logΩ / □ or more and 12 logΩ / □ or less, and the tubular body is applied as a recording medium conveying transfer belt. In this case, it is preferably 9.5 logΩ / □ or more and 11.5 logΩ / □ or less.
The surface resistivity is a measured value when measured by applying a voltage of 100 V in a normal temperature and normal humidity (temperature 22 ° C., humidity 55 RH%) environment.
The “average surface resistivity of the tubular body” is the normal temperature and humidity (temperature 22 ° C., humidity 55 RH%) at a total of 32 points of 4 points in the axial direction and 8 points in the circumferential direction on the outer peripheral surface of the tubular body. ) The above measurement is performed by applying a voltage of 100 V under the environment, and the average value is said.
Further, the “variation in surface resistivity” refers to a value obtained as a difference between the maximum value and the minimum value of the surface resistivity at the 32 points, which is measured in the same manner as the average surface resistivity of the tubular body.

The tubular body according to this embodiment has a surface resistivity when measured by applying a voltage of 100 V in a normal temperature and normal humidity (temperature 22 ° C, humidity 55RH%) environment, and normal temperature and normal humidity (temperature 22 ° C, humidity 55RH%). The difference between the surface resistivity when measured by applying a voltage of 1000 V under the environment is preferably 1.0 logΩ / □ or less.
The tubular body according to the present embodiment has a surface resistivity when measured by applying a voltage of 100 V in a low-temperature and low-humidity (temperature 10 ° C., humidity 10 RH%) environment, and a high temperature and high humidity (temperature 30 ° C., humidity 85 RH%). The difference between the surface resistivity when measured by applying a voltage of 100 V under the environment is preferably 1.0 logΩ / □ or less.

  Here, the surface resistivity is in accordance with JIS-K-6911 (1995), a circular electrode (UR probe of Hiresta IP manufactured by Mitsubishi Yuka Co., Ltd .: cylindrical electrode outer diameter Φ16 mm, ring-shaped electrode portion Current diameter flowing from the outer diameter to the inner diameter after 5 seconds after applying the target voltage under the target environment. Is obtained by using a microammeter R8340A manufactured by Advantest and obtained from the surface resistance value obtained from the current value.

-Manufacturing method-
The tubular body according to the present embodiment includes a kneading step for kneading crystalline resin, carbon black, and nigrosine dye, and a molding step for shaping the kneaded product obtained in the kneading step into a tubular shape. Manufactured by a manufacturing method.

Hereinafter, the manufacturing method of the tubular body concerning this embodiment is explained.
First, a crystalline resin, carbon black, nigrosine dye, and, if necessary, other additives are kneaded and mixed in desired amounts to obtain a kneaded product, and then, for example, using an extruder Then, it is extruded into a cylindrical shape and cooled and solidified to obtain a cylindrical shaped body. Then, the obtained cylindrical molded body is cut into a target width to obtain a tubular body.

  The tubular body according to the present embodiment can be applied to, for example, a belt for an image forming apparatus (specifically, an intermediate transfer belt or a recording medium conveyance belt).

(Tubular body unit)
FIG. 1 is a schematic perspective view showing a tubular body unit according to the present embodiment.
As shown in FIG. 1, the tubular body unit 130 according to the present embodiment includes the tubular body 10 according to the present embodiment. For example, the tubular body 10 includes a driving roll 131 and a driven roll that are arranged to face each other. It is stretched by 132 in the state where tension was applied.
Here, in the case where the tubular body 10 is applied as an intermediate transfer body, the tubular body unit 130 according to the present embodiment uses a roll that supports the tubular body 10 to transfer a toner image on the surface of the photoreceptor (image holding body) to the tubular body 10. A roll for primary transfer above and a roll for secondary transfer of the toner image transferred onto the tubular body 10 to the recording medium may be disposed.
In addition, the number of rolls that support the tubular body 10 is not limited, and may be arranged according to the usage mode. The tubular body unit 130 having the above configuration is used by being incorporated in the apparatus, and rotates while the tubular body 10 is also supported as the driving roll 131 and the driven roll 132 rotate.

(Image forming device)
The image forming apparatus according to the present embodiment includes an image carrier, a charging unit that charges the surface of the image carrier, a latent image forming unit that forms a latent image on the surface of the image carrier, and developing the latent image with toner. The image forming apparatus includes a developing unit that forms a toner image and a transfer unit that transfers the toner image to a recording medium. The transfer unit includes the tubular body according to the present embodiment.
Specifically, in the image forming apparatus according to the present embodiment, for example, the transfer unit includes an intermediate transfer member, a primary transfer unit that primarily transfers a toner image formed on the image holding member to the intermediate transfer member, and the intermediate transfer member. And a secondary transfer unit that secondarily transfers the toner image transferred to the recording medium, and the intermediate transfer body includes the tubular body according to the present embodiment.

  In the image forming apparatus according to the present embodiment, for example, the toner image formed on the image transfer body (conveyance transfer belt) for the transfer unit to convey the recording medium and the toner image formed on the image holder are conveyed by the paper transfer body. And a transfer means for transferring to a recording medium, and the recording medium transfer body includes the tubular body according to the present embodiment.

  The image forming apparatus according to the present embodiment is, for example, a normal monocolor image forming apparatus in which only a single color toner is accommodated in a developing device, and a toner image held on an image holding member is sequentially subjected to primary transfer to an intermediate transfer member. Examples include a repetitive color image forming apparatus and a tandem type color image forming apparatus in which a plurality of image holding bodies each having a developing device for each color are arranged in series on an intermediate transfer body.

Hereinafter, an image forming apparatus according to the present embodiment will be described with reference to the drawings.
FIG. 2 is a schematic configuration diagram illustrating the image forming apparatus according to the embodiment.

  As shown in FIG. 2, the image forming apparatus 100 according to the present embodiment is, for example, a so-called tandem method, and around the four image carriers 101 a to 101 d made of an electrophotographic photosensitive member along the rotation direction. In order, charging devices 102a to 102d, exposure devices 114a to 114d, developing devices 103a to 103d, primary transfer devices (primary transfer rolls) 105a to 105d, and image carrier cleaning devices 104a to 104d are arranged. Note that a static eliminator may be provided in order to remove residual potential remaining on the surfaces of the image carriers 101a to 101d after transfer.

  The intermediate transfer belt 107 is supported while applying tension by the support rolls 106a to 106d, the drive roll 111, and the opposing roll 108, thereby forming a tubular body unit 107b. With the support rolls 106a to 106d, the driving roll 111, and the opposing roll 108, the intermediate transfer belt 107 is in contact with the surfaces of the image carriers 101a to 101d, and the image carriers 101a to 101d and the primary transfer rollers 105a to 105d. Can be moved in the direction of arrow A. A portion where the primary transfer rolls 105a to 105d come into contact with the image carriers 101a to 101d via the intermediate transfer belt 107 is a primary transfer portion, and a primary contact portion between the image carriers 101a to 101d and the primary transfer rollers 105a to 105d is a primary transfer portion. A transfer voltage is applied.

  As a secondary transfer device, a counter roll 108 and a secondary transfer roll 109 are arranged to face each other with an intermediate transfer belt 107 and a secondary transfer belt 116 interposed therebetween. The recording medium 115 such as paper moves in the direction of the arrow B while being in contact with the surface of the intermediate transfer belt 107 while being in contact with the surface of the intermediate transfer belt 107, and then passes through the fixing device 110. A portion where the secondary transfer roll 109 comes into contact with the opposing roll 108 via the intermediate transfer belt 107 and the secondary transfer belt 116 is a secondary transfer portion, and the secondary transfer roll 109 and the opposing roll 108 are in contact with the secondary transfer portion. A transfer voltage is applied. Further, intermediate transfer belt cleaning devices 112 and 113 are arranged so as to come into contact with the intermediate transfer belt 107 after transfer.

  In the multicolor image forming apparatus 100 having this configuration, the image carrier 101a rotates in the direction of the arrow C, and the surface thereof is charged by the charging device 102a. An electrostatic latent image is formed. The formed electrostatic latent image is developed (developed) with a developer containing toner by a developing device 103a containing toner corresponding to the color to form a toner image. The developing devices 103a to 103d contain toners (for example, yellow, magenta, cyan, and black) corresponding to the electrostatic latent images of the respective colors.

  The toner image formed on the image carrier 101a is electrostatically transferred (primary transfer) onto the intermediate transfer belt 107 by the primary transfer roll 105a when passing through the primary transfer portion. Thereafter, the first, second and third color toner images are primarily transferred onto the intermediate transfer belt 107 holding the first color toner image by the primary transfer rolls 105b to 105d so that the toner images of the second color, the third color, and the fourth color are sequentially superimposed. Finally, a multi-colored multiple toner image is obtained.

  The multiple toner images formed on the intermediate transfer belt 107 are electrostatically collectively transferred to the recording medium 115 when passing through the secondary transfer portion. The recording medium 115 onto which the toner image has been transferred is conveyed to the fixing device 110, subjected to fixing processing by heating and pressing, or heating or pressing, and then discharged outside the apparatus.

  Residual toner is removed from the image carriers 101a to 101d after the primary transfer by the image carrier cleaning devices 104a to 104d. On the other hand, residual toner is removed from the intermediate transfer belt 107 after the secondary transfer by the intermediate transfer belt cleaning devices 112 and 113 to prepare for the next image forming process.

-Image carrier-
As the image carriers 101a to 101d, known electrophotographic photoreceptors are widely applied. As the electrophotographic photoreceptor, an inorganic photoreceptor having a photosensitive layer made of an inorganic material, an organic photoreceptor having a photosensitive layer made of an organic material, or the like is used. In organic photoconductors, a function-separated type organic photoconductor that stacks a charge generation layer that generates charge upon exposure and a charge transport layer that transports charge, or a single layer that performs the function of generating charge and the function of transporting charge Type organic photoreceptors are preferably used. In addition, as the inorganic photoconductor, a photoconductive layer composed of amorphous silicon is preferably used.

  The shape of the image carrier is not particularly limited, and a known shape such as a cylindrical drum shape, a sheet shape, or a plate shape is employed.

-Charging device-
The charging devices 102a to 102d are not particularly limited, and are, for example, conductive (here, “conductive” in the charging device means, for example, a volume resistivity of less than 10 ⁷ Ω · cm) or semiconductive. (Here, “semiconductive” in the charging device means, for example, a volume resistivity of 10 ^{7 to} 10 ¹³ Ωcm.) A contact-type charger or corona using a roller, brush, film, rubber blade or the like Known chargers such as scorotron chargers and corotron chargers using discharge are widely applied. Among these, a contact charger is preferable.

  The charging devices 102a to 102d normally apply a direct current to the image carriers 101a to 101d, but an alternating current may be further superimposed and applied.

-Exposure device-
There are no particular limitations on the exposure apparatuses 114a to 114d, and for example, a light source such as a semiconductor laser light, an LED (Light Emitting Diode) light, or a liquid crystal shutter light on the surfaces of the image carriers 101a to 101d, or these A well-known exposure apparatus such as an optical system apparatus capable of performing imagewise exposure from a light source via a polygon mirror is widely applied.

-Developer-
The developing devices 103a to 103d are selected according to the purpose. For example, a known developing device that develops a one-component developer or a two-component developer in a contact or non-contact manner using a brush or a roller can be used.

-Primary transfer roll-
The primary transfer rolls 105a to 105d may be either a single layer or a multilayer. For example, in the case of a single layer structure, it is composed of a roll in which an appropriate amount of conductive particles such as carbon black is blended in foamed or non-foamed silicone rubber, urethane rubber, EPDM, or the like.

-Image carrier cleaning device-
The image carrier cleaning devices 104a to 104d are for removing residual toner adhering to the surfaces of the image carriers 101a to 101d after the primary transfer process. In addition to the cleaning blade, brush cleaning or roll cleaning is performed. Used. Among these, it is desirable to use a cleaning blade. Examples of the material for the cleaning blade include urethane rubber, neoprene rubber, and silicone rubber.

-Secondary transfer roll-
The layer structure of the secondary transfer roll 109 is not particularly limited. For example, in the case of a three-layer structure, the layer structure includes a core layer, an intermediate layer, and a coating layer that covers the surface. The core layer is a foamed material such as silicone rubber, urethane rubber, or EPDM in which conductive particles are dispersed, and the intermediate layer is composed of these non-foamed materials. Examples of the material for the coating layer include tetrafluoroethylene-hexafluoropropylene copolymer or perfluoroalkoxy resin. The volume resistivity of the secondary transfer roll 109 is desirably 10 ⁷ Ωcm or less. Moreover, it is good also as a two-layer structure except an intermediate | middle layer.

-Opposed roll-
The counter roll 108 forms a counter electrode of the secondary transfer roll 109. The layer structure of the facing roll 108 may be either a single layer or a multilayer. For example, in the case of a single layer structure, it is composed of a roll in which an appropriate amount of conductive particles such as carbon black is blended in silicone rubber, urethane rubber, EPDM, or the like. In the case of a two-layer structure, it is composed of a roll in which the outer peripheral surface of the elastic layer made of the rubber material is covered with a high resistance layer.

  A voltage of 1 kV or more and 6 kV or less is normally applied to the core of the opposing roll 108 and the secondary transfer roll 109. Instead of applying a voltage to the core of the opposing roll 108, a voltage may be applied to the electrically conductive electrode member brought into contact with the opposing roll 108 and the secondary transfer roll 109. Examples of the electrode member include a metal roll, a conductive rubber roll, a conductive brush, a metal plate, or a conductive resin plate.

-Fixing device-
As the fixing device 110, for example, a known fixing device such as a heat roller fixing device, a pressure roller fixing device, or a flash fixing device is widely applied.

-Intermediate transfer belt cleaning device-
As the intermediate transfer belt cleaning devices 112 and 113, brush cleaning, roll cleaning, or the like is used in addition to the cleaning blade. Among these, it is desirable to use the cleaning blade. Examples of the material for the cleaning blade include urethane rubber, neoprene rubber, and silicone rubber.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. In the following, “part” is based on mass unless otherwise specified.

[Example 1]
Melt kneading 100 parts of polyphenylene sulfide resin (PPS, T1881-3, manufactured by Toray Industries, Inc., melting temperature: 285 ° C.) as a crystalline resin, and carbon black (Printex alpha, manufactured by Orion Engineered Carbon Co., Ltd., average primary particles as a conductive agent 27 parts of diameter: 20 nm) and 5 parts of nigrosine (SOM-L-0468, manufactured by Orient Chemical Industries) as a nigrosine dye were prepared. Using a biaxial extrusion melt kneader (L / D60, manufactured by Parker Corporation), the above-mentioned amounts of carbon black and nigrosine dye are blended in the melted PPS resin and melt kneaded, and the kneaded melt is placed in a water tank. And solidified by cooling and cut into a predetermined size to obtain mixed resin pellets containing carbon black.

-Molding of tubular body The obtained pellets are put into a uniaxial melt extruder (φ40mm, L / D: 30, melt extruder, manufactured by Ikegai Co., Ltd.), the maximum heating temperature of the uniaxial melt extruder is 330 ° C, and the extrusion processing temperature is 300. While melt-extruding from the gap between the mold die and nipple set at ℃, cool the outer surface of the cylindrical inner sizing die in contact with the inner peripheral surface of the molten resin, and then cut to the specified width, A tubular body having a thickness of 95 to 105 μm (average film thickness of 100 μm) was obtained. The obtained tubular body had a diameter of 160 mm, a width of 235 mm, and a thickness of 0.10 mm.

[Examples 2 to 4, Comparative Examples 1 to 3]
A tubular body was obtained by the same procedure as in Example 1 except that the type of resin used, the type and amount of carbon black used, and the amount of nigrosine dye used were as shown in Table 1.
In Table 1, “Printex 90” means “carbon black (Printex 90, manufactured by Orion Engineered Carbon, average primary particle size: 14 nm)”, and “Nylon 12” is “nylon 12 (Amilan SP500). , Manufactured by Toray Industries, Inc., melting temperature: 176 ° C.).

-Evaluation-
(Measurement of surface resistivity)
With respect to the obtained tubular body, “average surface resistivity of the tubular body” and “variation of surface resistivity” were determined by the above-described methods. The results are shown in Table 1.

(Measurement of image density unevenness)
The obtained tubular body was incorporated in DocuPrint CP200W manufactured by Fuji Xerox Co., Ltd. as an intermediate transfer body, and a halftone image (magenta density 30%) was formed on an A4 size OHP sheet in a low temperature and low humidity environment of 10 ° C. and 15% RH. 10 sheets were output continuously. The sheet output by OHP was projected, and the color unevenness was visually evaluated. The evaluation criteria are as follows.
G1: No image density unevenness G2: Image density unevenness

As can be seen from the results in Table 1, in the examples, it can be seen that the variation in surface resistivity is small compared to Comparative Example 1 that does not contain nigrosine dye and Comparative Example 3 that contains less nigrosine dye.
In Comparative Example 2 in which the content of nigrosine dye is too large, the average surface resistivity is 12.7 logΩ / □ even when the maximum amount of carbon black that maintains the strength of the tubular body is added. It was difficult to adjust the resistivity low.

DESCRIPTION OF SYMBOLS 10 Tubular body 100 Image forming apparatus 101a-101d Image holding body 102a-102d Charging apparatus 103a-103d Developing apparatus 104a-104d Image holding body cleaning apparatus 105a-105d Primary transfer roll 106a-106d Support roll 107 Intermediate transfer belt 107b, 130 Tubular Body unit 108 Opposing roll 109 Secondary transfer roll 110 Fixing device 111 Drive rolls 112 and 113 Intermediate transfer belt cleaning devices 114a to 114d Exposure device 115 Recording medium 116 Secondary transfer belt 131 Drive roll 132 Followed roll

Claims (6)

A crystalline resin;
Carbon black,
0.5 to 5 parts by mass of nigrosine dye with respect to 100 parts by mass of the crystalline resin,
An intermediate transfer member comprising a tubular body containing The intermediate transfer member according to claim 1, wherein the crystalline resin is a polyphenylene sulfide resin. The intermediate transfer member according to claim 1 or 2, wherein an average primary particle size of the carbon black is 25 nm or less. A tubular body constituting the intermediate transfer body according to any one of claims 1 to 3, and a plurality of rolls that span the tubular body in a tensioned state, and is attached to and detached from the image forming apparatus Tubular body unit. An image carrier,
Charging means for charging the surface of the image carrier;
Latent image forming means for forming a latent image on the surface of the charged image carrier;
Developing means for developing a latent image on the surface of the image carrier with toner to form a toner image;
The intermediate transfer member according to any one of claims 1 to 3 , wherein the toner image formed on a surface of the image carrier is transferred.
Primary transfer means for primarily transferring the toner image formed on the surface of the image carrier to the surface of the intermediate transfer member;
Secondary transfer means for secondary transfer of the toner image transferred to the surface of the intermediate transfer body to a recording medium;
An image forming apparatus comprising: The intermediate transfer member according to any one of claims 1 to 3 ,
An image carrier, a charging unit for charging the surface of the image carrier, a latent image forming unit for forming a latent image on the charged surface of the image carrier, and developing a latent image on the surface of the image carrier with toner. Development means for forming a toner image, primary transfer means for primary transfer of the toner image formed on the surface of the image holding member to the surface of the intermediate transfer member, and the toner image transferred to the surface of the intermediate transfer member. Secondary transfer means for secondary transfer to the recording medium, cleaning means for cleaning the surface of the intermediate transfer body after the toner image is secondarily transferred, and fixing for fixing the toner image transferred to the recording medium At least one selected from means;
And a process cartridge which is detachable from the image forming apparatus.