JP2017025213A - Surface-treated carbon black for image forming apparatus, tubular body for image forming apparatus, tubular body unit for image forming apparatus, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface-treated carbon black for an image forming apparatus, which suppresses occurrence of cracking of an outer peripheral surface of a tubular body when the outer peripheral surface has been repeatedly deformed, compared to the case where a tubular body for an image forming apparatus is manufactured, in which the outer peripheral surface is configured of a resin layer containing a resin and only a carbon black that is not surface-treated, as carbon black.SOLUTION: There is provided a surface-treated carbon black for an image forming apparatus, which is surface-treated with silane or titanate.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a surface-treated carbon black for an image forming apparatus, a tubular body for an image forming apparatus, a tubular body unit for an image forming apparatus, and an image forming apparatus.

  Patent Document 1 discloses a silicone-treated carbon black characterized by treating carbon black having a DBP oil absorption of 100 ml / 100 g or more and 600 ml / 100 g or less with a treatment agent containing at least hydrogen polysiloxane.

  Patent Document 2 discloses an endless belt used in an image forming apparatus, which mainly includes a thermoplastic polymer component made of a thermoplastic resin and / or a thermoplastic elastomer, and the thermoplastic polymer component and carbon black are mixed by heating. In the endless belt for an image forming apparatus obtained by extrusion molding, the pH of the carbon black is 4 or more, and silicone is attached to the carbon black prior to heating and mixing the thermoplastic polymer component and the carbon black. An endless belt for an image forming apparatus is disclosed, wherein the functional group equivalent of the silicone is 500 g / mol or more.

Japanese Patent No. 4845454 Japanese Patent No. 5082464

  In the present invention, a tubular body for an image forming apparatus in which an outer peripheral surface is constituted by a resin and a resin layer containing only carbon black that has not been surface-treated as carbon black (hereinafter sometimes referred to simply as “tubular body”). It is an object of the present invention to provide a surface-treated carbon black for an image forming apparatus in which the occurrence of cracks on the outer peripheral surface is suppressed when the outer peripheral surface of the tubular body is repeatedly deformed as compared with the case of manufacturing the above.

In order to achieve the above object, the following invention is provided.
The invention according to claim 1 is a surface-treated carbon black for an image forming apparatus, which is surface-treated with silane or titanate.

The invention according to claim 2 is for an image forming apparatus having a resin layer containing a resin and the surface-treated carbon black for an image forming apparatus according to claim 1, and having an outer peripheral surface constituted by the resin layer. Tubular body.
The invention according to claim 3 is the tubular body for an image forming apparatus according to claim 2, wherein the surface-treated carbon black for the image forming apparatus has an average primary particle diameter of 30 nm or less.
According to a fourth aspect of the present invention, the content of the surface-treated carbon black for an image forming apparatus with respect to 100 parts by mass of the resin contained in the resin layer is 10 parts by mass or more and 30 parts by mass or less. 4. A tubular body for an image forming apparatus according to 3.

  An invention according to claim 5 is an image forming apparatus comprising: the tubular body for an image forming apparatus according to any one of claims 2 to 4; and a support that supports the tubular body for the image forming apparatus. Tubular body unit.

An invention according to claim 6 is an image forming apparatus comprising the tubular body for an image forming apparatus according to any one of claims 2 to 4.
According to a seventh aspect of the present invention, there is provided 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 surface of the charged image carrier, and the image carrier. The latent image on the surface of the toner is developed with a developer containing toner to form a toner image, and the intermediate transfer which is the tubular body for an image forming apparatus according to any one of claims 2 to 4. A belt, primary transfer means for primarily transferring the toner image formed on the surface of the image carrier to the outer peripheral surface of the intermediate transfer belt, and the toner image transferred to the outer peripheral surface of the intermediate transfer belt as a recording medium. An image forming apparatus.

  According to the first aspect of the present invention, the tubular body for an image forming apparatus in which the outer peripheral surface is constituted by the resin and the resin layer containing only carbon black that has not been surface-treated as carbon black is more tubular than the case of manufacturing the tubular body for an image forming apparatus. Provided is a surface-treated carbon black for an image forming apparatus in which occurrence of cracks on the outer peripheral surface is suppressed when the outer peripheral surface of the body is repeatedly deformed.

According to the invention of claim 2, the outer peripheral surface of the tubular body as compared with the tubular body for an image forming apparatus in which the outer peripheral surface is constituted by a resin and a resin layer containing only carbon black that is not surface-treated as carbon black. There is provided a tubular body for an image forming apparatus in which the occurrence of cracks on the outer peripheral surface is suppressed when is repeatedly deformed.
According to the third aspect of the present invention, compared to the case where the average primary particle diameter of the surface-treated carbon black for the image forming apparatus contained in the resin layer exceeds 30 nm, the outer peripheral surface of the tubular body for the image forming apparatus has poor cleaning. A tubular body for an image forming apparatus to be suppressed is provided.
According to the invention which concerns on Claim 4, compared with the case where content of the said surface treatment carbon black for image forming apparatuses exceeds 30 mass parts with respect to 100 mass parts of said resin contained in the said resin layer, it is a tubular body. There is provided a tubular body for an image forming apparatus in which occurrence of cracks on the outer peripheral surface is suppressed when the outer peripheral surface is repeatedly deformed.

  According to the invention which concerns on Claim 5, compared with the case where it comprises the tubular body for image forming apparatuses by which the outer peripheral surface is comprised by resin and the resin layer containing only the carbon black which is not surface-treated as carbon black, a tubular body There is provided a tubular body unit for an image forming apparatus in which the occurrence of cracks on the outer peripheral surface is suppressed when the outer peripheral surface of the outer peripheral surface is repeatedly deformed.

According to the sixth aspect of the present invention, the tubular body is provided as compared with the case where the tubular body for the image forming apparatus having the outer peripheral surface constituted by the resin and the resin layer containing only the carbon black not subjected to the surface treatment as the carbon black is provided. There is provided an image forming apparatus in which the occurrence of cracks on the outer peripheral surface is suppressed when the outer peripheral surface is repeatedly deformed.
According to the seventh aspect of the present invention, the outer periphery of the intermediate transfer belt is compared with the case where an intermediate transfer belt having an outer peripheral surface constituted by resin and a resin layer containing only carbon black that has not been surface-treated as carbon black is provided. An image forming apparatus is provided in which occurrence of image defects due to surface cracks is suppressed.

It is a schematic diagram which shows an example of the surface treatment carbon black for image forming apparatuses which concerns on this embodiment. It is a schematic diagram which shows the other example of the surface treatment carbon black for image forming apparatuses which concerns on this embodiment. It is a schematic perspective view which shows an example of the tubular body unit for image forming apparatuses which concerns on this embodiment. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an exemplary embodiment.

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

[Surface treatment carbon black for image forming equipment]
The surface-treated carbon black for an image forming apparatus according to this embodiment (hereinafter sometimes referred to as “surface-treated carbon black”) is carbon black whose surface is surface-treated with silane or titanate. Hereinafter, carbon black surface-treated with silane may be referred to as “silane-treated carbon black”, and carbon black surface-treated with titanate may be referred to as “titanate-treated carbon black”.

The surface-treated carbon black according to this embodiment is used as a conductive agent for a conductive member in an image forming apparatus.
For example, when a tubular body having an outer peripheral surface constituted by a resin layer formed by blending the surface-treated carbon black according to the present embodiment with a resin is produced, the outer peripheral surface is deformed when the outer peripheral surface of the tubular body is repeatedly deformed. The occurrence of cracks is suppressed. The reason is presumed as follows.
By surface treating carbon black with silane or titanate, the affinity between surface functional groups derived from silane or titanate and bonded to the surface of carbon black and polar groups such as amide groups, imide groups and ether groups of the resin By improving the property (entanglement between molecules) and increasing the dispersibility of carbon black in the resin, the intermolecular force between the carbon black and the resin acts strongly and the binding force at the interface is improved. It is thought that cracking (cracking) does not easily occur on the surface of the tubular body, and bending durability is improved.
In addition, the surface-treated carbon black according to the present embodiment has high dispersibility, and the resin is easily attached to the surface without any gap, so that the unevenness of the belt surface is reduced and smoothed.

  The carbon black before being surface-treated with silane or titanate in the present embodiment is not particularly limited, and examples thereof include ketjen black, oil furnace black, channel black, acetylene black, and carbon black whose surface has been oxidized (surface oxidation treatment). Carbon black), graphitized carbon black whose surface is graphitized, and the like.

The average primary particle size of the surface-treated carbon black according to this embodiment is preferably 30 nm or less, more preferably 13 nm or more and 25 nm or less, and still more preferably 13 nm or more and 20 nm or less. When the average primary particle size of the surface-treated carbon black according to this embodiment is 30 nm or less, the proportion of the surface-treated carbon black particles per unit area in the resin layer of the tubular body according to this embodiment can be increased. it can.
Due to the synergistic effect of the surface treatment (silane treatment or titanate treatment) according to this embodiment and the average primary particle size of 30 nm or less, the bonding force between the resin and the surface-treated carbon black is increased, and cracking of the outer peripheral surface due to repeated deformation Generation | occurrence | production is suppressed effectively and the stability of surface resistance and the improvement of surface smoothness are also aimed at by disperse | distributing the surface-treated carbon black of a smaller particle diameter in resin.

The average primary particle size of the surface-treated carbon black according to the present embodiment was determined by observing 50 randomly selected surface-treated carbon blacks with a TEM (transmission electron microscope), and the diameter of a circle equal to the projected area of each particle. Is the particle size, and the average value is the average primary particle size.
In addition, when the surface-treated carbon black according to the present embodiment is included in the tubular body, the tubular body is cut with a microtome to collect a measurement sample, 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 randomly selected surface-treated carbon black particles is defined as the particle diameter, and the average value thereof is defined as the average primary particle diameter.

  In general, the smaller the average primary particle size of carbon black, the easier it is to aggregate and the more difficult it is to disperse in the resin. However, the surface-treated carbon black according to the present embodiment is easily dispersed by being treated with silane or titanate. For example, even when the average primary particle size is 30 nm or less, good dispersibility is obtained. Therefore, if the image forming apparatus includes a tubular body having an outer peripheral surface constituted by a resin layer formed using a resin composition containing the surface-treated carbon black according to the present embodiment, for example, as an intermediate transfer belt, carbon Image defects caused by unevenness on the outer peripheral surface due to black aggregation are less likely to occur, and fluctuations in electrical resistance are also suppressed. Therefore, occurrence of streaky omission of the toner image due to fluctuations in image density or poor cleaning when image formation is continuously performed is suppressed.

  Here, the manufacturing method of the surface treatment carbon black which concerns on this embodiment is demonstrated.

(Silane treatment)
When carbon black is surface-treated with silane to produce the surface-treated carbon black according to this embodiment, examples of silane include chlorosilane and alkoxysilane, and alkylalkoxysilane is preferable.
Examples of the alkylalkoxysilane include methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, isobutyltrimethoxysilane, n-butyltrimethoxysilane, n-hexyltrimethoxysilane, n-octyltrimethoxysilane, n- Octyltriethoxysilane, n-decyltrimethoxysilane and the like, and examples of the fluoroalkylalkoxysilane compound include trifluoropropyltrimethoxysilane, tridecafluorooctyltrimethoxysilane, heptadecafluorodecyltrimethoxysilane, and heptadecafluoro. Decylmethyldimethoxysilane, (tridecafluoro-1,1,2,2-tetrahydrooctyl) triethoxysilane, (3,3,3-trifluoropropyl) trimeth Shishiran, (heptadecafluoro-1,1,2,2-tetrahydrodecyl) triethoxysilane, 3- (heptafluoroisopropoxy) propyltriethoxysilane, and the like. Particularly preferred is an alkylalkoxysilane represented by the following formula (1).

In Formula (1), R ¹ represents a linear or branched alkyl group having 1 to 5 carbon atoms, R ² represents a linear or branched alkyl group having 1 to 10 carbon atoms, and m is 1 or more. Represents an integer of 3 or less.
The alkyl group represented by R ¹ preferably has 1 to 5 carbon atoms, and more preferably 1 to 3 carbon atoms.
The alkyl group represented by R ² preferably has 1 to 10 carbon atoms, and more preferably 1 to 8 carbon atoms.
m is preferably 2 or more and 3 or less, and more preferably 3.
Specifically, n-octyltriethoxysilane or the like can be suitably used as the silane used for the silane treatment.

  For example, when the surface treatment of carbon black is performed using n-octyltriethoxysilane, for example, the following method may be mentioned.

  A predetermined amount of carbon black is added to a Henschel mixer and pre-stirred at 50 rpm for 5 minutes. Then, a predetermined amount of silanizing agent having n-octyltriethoxysilane is added and mixed in the Henschel mixer for 10 minutes, and the surface is silanized. A treated carbon black is produced.

For example, when surface treatment of carbon black is performed using n-octyltriethoxysilane represented by the following formula, as shown in FIG. 1, the CH ₃ (CH ₂ ) ₇ SiO moiety is carbon black 20 via oxygen. It is considered that the silanes generate -Si-O-S- bonds while bonding to the surface of each other.

(Titanate treatment)
When the surface-treated carbon black according to this embodiment is produced by surface-treating carbon black with titanate, examples of the titanate include an alkoxytitanium ester, a titanium chelate, and a titanium acylate having a Ti—O—C type bond. .
Specifically, isopropyl triisostearoyl titanate, isopropyl tridodecyl benzene sulfonyl titanate, isopropyl tris (dioctyl bisphosphate) titanate, tetraisopropyl bis (dioctyl phosphite) titanate, tetraoctyl bis (ditridecyl phosphite) titanate, tetra ( 2,2-diallyloxymethyl-1-butyl) bis (di-tridecyl) phosphite titanate, bis (dioctyl borophosphate) oxyacetate titanate, bis (dioctyl bisphosphate) ethylene titanate, isopropyl trioctanoyl titanate, isopropyl dimethacryl Isostearoyl titanate, isopropyl tri (dioctyl phosphate) titanate, isopropyl Riku mill phenyl titanate, isopropyl tri (N- aminoethyl-aminoethyl) titanate, dicumyl phenyloxy acetate titanate, diisostearoyl ethylene titanate. In particular, an alkoxytitanium ester represented by the following formula (2) is preferable.

In Formula (2), R ³ represents a linear or branched alkyl group having 1 to 8 carbon atoms, R ⁴ represents a linear or branched alkyl group having 1 to 20 carbon atoms, and n is 1 or more. Represents an integer of 3 or less.
The alkyl group represented by R ³ preferably has 1 to 6 carbon atoms, and more preferably 1 to 4 carbon atoms.
The number of carbon atoms of the alkyl group represented by R ⁴ is more preferably 1 or more and 18 or less.
n is preferably 2 or more and 3 or less, more preferably 3.
Specifically, isopropyl triisostearoyl titanate or the like can be preferably used as the titanate used for the titanate treatment.

For example, when the surface treatment of carbon black is performed using isopropyl triisostearoyl titanate, for example, the following method may be mentioned.
A predetermined amount of carbon black was added to a Henschel mixer and pre-stirred at 50 rpm for 5 minutes, and then a predetermined amount of titanating agent having isopropyl triisostearoyl titanate was added and mixed in the Henschel mixer for 10 minutes to be titanated. Carbon black is produced.

  For example, when the surface treatment of carbon black is performed using isopropyl triisostearoyl titanate represented by the following formula, as shown in FIG. 2, the surface of the carbon black 20 is bonded via oxygen bonded to the isopropyl group. It is thought to combine.

[Tubular body for image forming apparatus]
The tubular body for an image forming apparatus according to the present embodiment has a resin layer containing a resin and the surface-treated carbon black according to the above-described embodiment, and an outer peripheral surface is configured by the resin layer.
The tubular body according to the present embodiment may be a single-layer tubular body having only the resin layer or a laminated tubular body having one or more other layers on the inner peripheral surface side of the resin layer.
Further, the tubular body according to the present embodiment may be a belt shape or a roll shape.
Hereinafter, as a representative example of the tubular body according to the present embodiment, a belt-shaped single-layer tubular body (hereinafter sometimes referred to as “tubular belt”) will be mainly described. However, the tubular body according to the present embodiment. Is not limited to a single-layer tubular belt.

(resin)
What is necessary is just to select resin contained in the tubular belt which concerns on this embodiment according to the use of a tubular belt.
Specific resins include, for example, polyetherimide (PEI), polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polyamide (PA), polyethersulfone (PES), polyphenylsulfone (PPSU), Polysulfone (PSF), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polyacetal (POM), polycarbonate (PC), polybenzimidazole (PBI), polyimide (PI), polyamideimide ( PAI), polyarylate (PAR), modified polyphenylene ether (m-PPE), fluororesin (FR), syndiotactic polystyrene (SPS), polyester elastomer (TPC), polyetherke Ton (PEK), polycycloolefin (COP), polymethylpentene (PMP), wholly aromatic polyester (liquid crystal polymer), and the like.
These resins may be used individually by 1 type, and 2 or more types may be mixed and used for them.
In view of moldability, strength, releasability and the like, a thermoplastic resin is preferable, and PEI, m-PPE, PPS, and PEEK are more preferable in consideration of manufacturing cost and the like.

(Surface treatment carbon black)
The tubular belt according to the present embodiment contains the surface-treated carbon black according to the present embodiment.
The content of the surface-treated carbon black contained in the tubular belt according to the present embodiment depends on the type of resin, the use of the tubular belt, and the like. For example, when used as an intermediate transfer belt of an image forming apparatus, the content is 100 parts by mass of the resin. The content of the surface-treated carbon black is preferably 10 to 30 parts by mass, more preferably 12 to 22 parts by mass, and particularly preferably 15 to 25 parts by mass.
If the content of the surface-treated carbon black is 10 parts by mass or more with respect to 100 parts by mass of the resin, sufficient conductivity as an intermediate transfer belt can be obtained, and if it is 30 parts by mass or less, high flexibility is obtained. And the occurrence of cracks due to repeated deformation can be effectively suppressed.
Since the surface-treated carbon black according to the present embodiment has high dispersibility, aggregation is suppressed even when the amount is relatively large. Therefore, by using the surface-treated carbon black according to this embodiment, a tubular belt having high conductivity and high in-plane conductivity uniformity can be obtained.

  The tubular belt according to the present embodiment includes carbon black other than the surface-treated carbon black, for example, carbon black not subjected to any surface treatment, carbon black subjected to a surface treatment other than silane treatment or titanate treatment. However, from the viewpoint of conductivity and flexibility, the total amount of carbon black with respect to 100 parts by mass of the resin is preferably 10 parts by mass or more and 30 parts by mass or less.

(Other additives)
The tubular belt according to the present embodiment may contain other additives as necessary in addition to the resin and the surface-treated carbon black. Examples of other additives include, for example, antioxidants for preventing thermal deterioration, surfactants for improving fluidity, heat aging inhibitors, and the like, which are particularly well-known additives blended in an endless belt of an image forming apparatus. Agents.

(Physical properties of tubular belt)
The tubular belt according to the present embodiment has a surface resistivity (average surface resistivity of the tubular body) of 7 logΩ / measuring 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, particularly when a tubular body is applied as an intermediate transfer belt, it is preferably 8 logΩ / □ or more and 12 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.
Further, the average surface resistivity of the tubular body is a normal temperature and normal humidity (temperature 22 ° C., humidity 55 RH%) environment 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. Thus, the above measurement is performed by applying a voltage of 100 V and the average is obtained.

  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.

(Method for producing tubular body)
The method for producing the tubular body according to the present embodiment is not particularly limited, and a known method can be employed except that the surface-treated carbon black according to the present embodiment is used as the conductive agent.
For example, a thermoplastic resin, surface-treated carbon black, and, if necessary, other additives are added to an extruder, kneaded, melt extruded into a tube, and cooled and solidified to obtain a cylindrical molded body. In the case of producing a tubular body having a laminated structure of two or more layers, for example, a cylindrical shape is formed by coextrusion so that a layer containing a thermoplastic resin, surface-treated carbon black, etc. becomes an outermost layer (surface layer). Can be obtained.

Alternatively, a coating solution containing a resin, surface-treated carbon black, a solvent, etc. is prepared, and the coating solution is applied to the outer peripheral surface of a cylindrical mold, and then heated and dried to form a film, which is peeled off from the mold and formed into a cylinder. A shaped product is obtained.
And the tubular body (tubular belt) which concerns on this embodiment is obtained by cut | disconnecting the obtained cylindrical molded object to the target width | variety.

  Moreover, when manufacturing a roll-shaped tubular body, such as a conductive roll, for example, a roll-shaped elastic layer is formed using a rubber material on the outer peripheral surface of a cylindrical or columnar support, while the resin, surface A tubular coated tube containing treated carbon black or the like is produced. And the tubular body which concerns on this embodiment can be manufactured by coat | covering the said coating tube as a resin layer on the outer peripheral surface of an elastic layer.

[Tubular body unit for image forming apparatus]
A tubular body unit for an image forming apparatus according to the present embodiment (hereinafter sometimes simply referred to as a “tubular unit”) includes the tubular body according to the present embodiment and a support that supports the tubular body. .
FIG. 3 is a schematic perspective view showing the tubular body unit according to the present embodiment. The tubular body unit 130 shown in FIG. 3 includes the tubular belt 10 as the tubular body according to the above-described embodiment. For example, the tubular belt 10 is tensioned by the drive roll 131 and the driven roll 132 arranged to face each other. It is supported by being stretched over.
For example, when the tubular belt 10 is applied as an intermediate transfer member, the tubular body unit 130 according to the present embodiment uses a roll that supports the tubular belt 10 to transfer a toner image on the surface of the photoreceptor (image holding member) to the tubular belt 10. A roll for primary transfer to the outer peripheral surface and a roll for further secondary transfer of the toner image transferred to the outer peripheral surface of the tubular belt 10 to the recording medium may be disposed.
In addition, the number of rolls that support the tubular belt 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 apparatus]
The image forming apparatus according to the present embodiment is an image forming apparatus including the tubular body for an image forming apparatus according to the present embodiment.
Here, examples of the tubular body in the image forming apparatus according to the present embodiment include an intermediate transfer belt, a conveyance belt that conveys a recording medium, a fixing belt, a pressure belt, a charging roll, a transfer roll, and a cooling belt.

  For example, when the intermediate transfer belt includes the tubular body according to the embodiment, the image forming apparatus according to the embodiment includes an image holding body, a charging unit that charges the surface of the image holding body, and the charged image. A latent image forming unit that forms a latent image on the surface of the holding member, a developing unit that develops the latent image on the surface of the image holding member with a developer containing toner, and a toner image according to the above embodiment. An intermediate transfer belt that is a tubular body, a primary transfer unit that primarily transfers the toner image formed on the surface of the image carrier to the outer peripheral surface of the intermediate transfer belt, and the intermediate transfer belt that has been transferred to the outer peripheral surface of the intermediate transfer belt Secondary transfer means for secondary transfer of the toner image to a recording medium.

  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 carrier is sequentially primary-transferred to an intermediate transfer belt. Examples include a color image forming apparatus that repeats, and a tandem type color image forming apparatus in which a plurality of image carriers including developing units of respective colors are arranged in series on an intermediate transfer belt.

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

FIG. 4 is a schematic configuration diagram illustrating an example of an image forming apparatus according to the present embodiment. The image forming apparatus shown in FIG. 4 is an image forming apparatus in which the tubular body according to the present embodiment is applied to an intermediate transfer belt.
As shown in FIG. 4, the image forming apparatus 100 according to the present embodiment is, for example, a so-called tandem method, and around 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 secondary transfer belt 116 is supported by a secondary transfer roll 109 and a support roll 106e. 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.

-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.

  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 toner images of the second color, the third color, and the fourth color are primarily transferred onto the intermediate transfer belt 107 holding the toner image of the first color 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.

  In such an image forming process, the intermediate transfer belt 107 rotates in the circumferential direction A while being supported by the support rolls 106a to 106d, the drive roll 111, and the like, and repeatedly deforms, but employs the tubular body according to the present embodiment. As a result, the occurrence of cracks on the outer peripheral surface is suppressed, and the occurrence of image defects such as streaky image omission due to the cracks on the outer peripheral surface of the belt is suppressed.

  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]
<Production of silane-treated carbon black 1>
As a carbon black, Monark 880 (manufactured by Cabot Specialty Chemicals, average primary particle size 16 nm) was used, and silane-treated carbon black 1 was produced as follows.
A predetermined amount of carbon black Monark 880 is put into a Henschel mixer, pre-stirred at 50 rpm for 5 minutes, and then a predetermined amount of silanizing agent having n-octyltriethoxysilane is added and mixed in the Henschel mixer for 10 minutes. Carbon black 1 subjected to the chemical treatment was produced.

(Surface treatment carbon black)
The average primary particle size of the carbon black after the surface treatment was measured by the method described above.

<Production of tubular belt 1>
-Preparation of resin pellets 100 parts by mass of polyetherimide (ULTEM1010V (manufactured by Savic)) as a thermoplastic resin was put into a biaxial extrusion melt kneader (biaxial melt kneading extruder L / D60 (manufactured by Parker Corporation)). . In the molten resin, 20 parts by mass of the carbon black 1 subjected to the silanization treatment was blended by side feed and melt-kneaded. The kneaded melt was extruded from the outlet of the melt kneader into a water tank and solidified by cooling. A strand (resin shape having a diameter of about 2 mm) obtained by cooling and solidification was inserted into a pelletizer and cut into a length of 5 mm to obtain pellets of a resin composition.

-Tubular belt molding Resin pellets are put into a uniaxial melt extruder (L / D24, melt extrusion equipment manufactured by Mitsuba Seisakusho Co., Ltd.) (heating temperature 340 ° C) and melted from the gap between the mold die and nipple set to 330 ° C. While extruding, the outer surface of the cylindrical inner sizing die was brought into contact with the inner peripheral surface of the molten resin and cooled. Thereafter, the obtained cylindrical molded body was cut to obtain a tubular belt 1 having an average film thickness of 120 μm.

[Example 2]
In producing the tubular belt 1 in Example 1, the tubular belt 2 was produced in the same manner as in Example 1 except that polyether ether ketone (VestaKeep 3300G (manufactured by Daicel Evonik)) was used as the resin.

[Example 3]
In polyamideimide varnish (HPC 7200, manufactured by Hitachi Chemical Co., Ltd.), 22 parts by mass of silanized carbon black 1 was added to 100 parts by mass of the solid content, and mixed and dispersed using a jet mill to obtain a coating solution.
As the metal core to be applied, an aluminum cylindrical body having an outer diameter of 302 mm and a length of 400 mm was used, and the surface roughness Ra of the core body surface was 0.5 μm by blasting the surface. Prepared. Further, a silicone release agent (trade name: KS700, manufactured by Shin-Etsu Chemical Co., Ltd.) was applied to the surface of the core, and baked at 300 ° C. for 1 hour.
On the other hand, as an annular body, a Teflon (registered trademark) ring having an outer diameter of 320 mm and a triangular cross section is fitted inside a stainless steel hollow ring having an outer diameter of 400 mm, an inner diameter of 320 mm, and a height of 30 mm. What was made to use was used. The minimum hole diameter of this Teflon (registered trademark) ring was 303.6 mm.
Next, after the annular body was floated on the coating solution, the annular body was fixed so as not to move, the core was axially perpendicular, inserted into the hole of the annular body at a speed of 500 mm / min, and immersed. . Next, the fixing of the annular body was released, and the core body was pulled up at a speed of 150 mm / min. During the pulling, the annular body did not contact the core, and a PI precursor coating film having a wet film thickness of about 700 μm was formed on the surface of the core. Next, the core body on which the PI precursor coating film was formed was placed in a drying furnace. The temperature was maintained at 320 ° C. for 2 hours and 320 ° C. for 30 minutes to obtain a polyimide tubular body. Since the release agent was previously applied to the surface of the core body, the inner peripheral surface of the tubular body did not adhere to the core body at the time of peeling. The tubular body had a thickness of 80 μm and a surface resistivity of 10.1 log / □.

[Example 4]
<Production of titanate-treated carbon black 2>
As carbon black, 20 parts of Monark 880 (manufactured by Cabot Specialty Chemicals) was used, and titanate-treated carbon black 2 was produced as follows.
A predetermined amount of carbon black was added to a Henschel mixer and pre-stirred at 50 rpm for 5 minutes, and then a predetermined amount of titanating agent having isopropyl triisostearoyl titanate was added and mixed in the Henschel mixer for 10 minutes to be titanated. Carbon black was produced.

<Production of tubular belt 4>
A tubular belt 4 was produced in the same manner as in Example 1 except that the conductive agent was changed to the titanate-treated carbon black 2 in the production of the tubular belt 1 in Example 1.

[Example 5]
<Production of silane-treated carbon black 3>
Silane-treated carbon black 3 was produced in the same manner as in Example 1 except that Hi-BLACK 30L (manufactured by Orion Engineered Carbons) was used as the carbon black in Example 1.

<Production of tubular belt 5>
A tubular belt 5 was produced in the same manner as in Example 1 except that the conductive agent was changed to the silane-treated carbon black 3 in the production of the tubular belt 1 in Example 1.

[Example 6]
<Production of silane-treated carbon black 4>
Silane-treated carbon black 4 was produced in the same manner as in Example 1 except that 20 parts of Hi-BLACK 5L (manufactured by Orion Engineered Carbons) was used as carbon black.

<Production of tubular belt 6>
A tubular belt 6 was produced in the same manner as in Example 1 except that the conductive agent was changed to the silane-treated carbon black 4 in the production of the tubular belt 1 in Example 1.

[Example 7]
<Preparation of tubular belt 7>
In the production of the tubular belt 1 in Example 1, the tubular belt was obtained in the same manner as in Example 1 except that the compounding amount of the silanized carbon black 1 was changed to 10 parts by mass with respect to 100 parts by mass of the resin (PEI). 7 was produced.

[Example 8]
<Production of tubular belt 8>
In the production of the tubular belt 1 in Example 1, the tubular belt was obtained in the same manner as in Example 1 except that the compounding amount of the silanized carbon black 1 was changed to 30 parts by mass with respect to 100 parts by mass of the resin (PEI). 8 was produced.

[Comparative Example 1]
<Production of tubular belt C1>
A tubular belt C1 was produced in the same manner as in Example 5 except that in the production of the tubular belt 5 in Example 5, the silane treatment of carbon black was not performed.

[Comparative Example 2]
<Production of tubular belt C2>
In the production of the tubular belt 1 in Example 6, a tubular belt C2 was produced in the same manner as in Example 6 except that the carbon black was not subjected to silane treatment.

[Evaluation]
The following evaluation was implemented about the tubular belt obtained by the Example or the comparative example.

(1) Repeated bending durability (times)
Test method: JIS-P8115 compliant (MIT test machine, sample width 15 mm, tensile load 1 kg until endurance)
The tubular belt obtained in each example was cut into a strip-like sample having a width of 15 mm and a length of 200 mm in the circumferential direction, both ends were fixed, and a tensile tension of 1 kgf was applied to normal temperature and humidity (temperature 22 ° C., humidity 55 RH%). ) Under the environment, the terminal having the curvature shape R0.38 was bent (bent) repeatedly in the left and right directions by 90 °. At this time, the number of times until the sample broke was evaluated as the number of bending resistances.

(2) Surface resistivity (logΩ / □)
The surface resistivity of the tubular belt obtained in each example was determined according to JIS-K-6911 (1995). Circular electrodes (UR probe of Hiresta IP manufactured by Mitsubishi Yuka Co., Ltd .: outer diameter of cylindrical electrode) Φ16mm, inner diameter of ring electrode part Φ30mm, outer diameter Φ40mm), place the object to be measured on the insulating plate, and load 2kg, voltage 100V under normal temperature and normal humidity (temperature 22 ℃, humidity 55RH%) environment. The current value flowing from the outer diameter to the inner diameter 10 seconds after application was measured by using a microammeter R8340A manufactured by Advantest, and obtained from the surface resistance value obtained from the current value.
Of the outer peripheral surface of the tubular belt, the above measurement was performed at a total of 32 points of 4 points in the axial direction (width direction) and 8 points in the circumferential direction, and the average value was defined as the surface resistivity.

(3) Surface smoothness The surface roughness Ra of the outer peripheral surface of the tubular belt obtained in each example was measured. Specifically, as a measuring device, a surfcom 1400D manufactured by Tokyo Seimitsu with a stylus with a tip of R2 μm and a pressure of 0.7 mN, a cutoff of 0.8 mm, a measuring length of 2.5 mm, and a moving speed of 0.6 mm / s The Ra value when measured under the conditions was read.

(4) Durability test for continuous transfer performance (actual machine test)
The tubular belt (endless belt) obtained in each example is mounted on DocuPrint C2250 manufactured by Fuji Xerox Co., Ltd. as an intermediate transfer belt of an image forming apparatus, in a low temperature and low humidity environment of 10 ° C./10% RH (intermediate transfer belt during transfer). In an environment where discharge due to paper peeling on the front surface is likely to occur), 50,000 sheets of halftone (magenta density 30%) images are output continuously to A4 size plain paper, and the 50,000th image. The image quality was evaluated. The image quality was evaluated according to the following criteria.
A: No image defect B: An image defect within an allowable range occurs C: An image defect that deviates from the allowable range occurs Here, specifically, the image defect is a streak-like image omission or an image density group.

The surface resistivity (log Ω / □) of the tubular belt (intermediate transfer belt) after continuous output of 50,000 images was measured in the same manner as described above.
Further, the state of occurrence of breakage and cracks at the belt end was confirmed visually and with a microscope.

  The results are shown in Table 1.

In the image evaluation in the actual machine endurance test, in Comparative Examples 1 and 2, image white streaks due to poor cleaning caused by the rough surface of the belt occurred. In addition, a crack occurred in a part of the belt end.
Further, in Comparative Example 2, halftone image density spots thought to be caused by a remarkable resistance drop also occurred.

10 Tubular belt (tubular body)
100 Image forming apparatus 101a to 101d Image carrier 102a to 102d Charging device (charging means)
103a to 103d Developing device (developing means)
104a to 104d Image carrier cleaning devices 105a to 105d Primary transfer rolls 106a to 106d Support roll 107 Intermediate transfer belt 107b, 130 Tubular body unit 108 Opposing roll 109 Secondary transfer roll 110 Fixing device (fixing means)
111 Driving rolls 112 and 113 Intermediate transfer belt cleaning devices 114a to 114d Exposure device (latent image forming means)
115 Recording Medium 116 Secondary Transfer Belt 131 Drive Roll 132 Followed Roll

Claims (7)

  A surface-treated carbon black for an image forming apparatus, which is surface-treated with silane or titanate.   The tubular body for image forming apparatuses which has a resin layer containing resin and the surface treatment carbon black for image forming apparatuses of Claim 1, and the outer peripheral surface is comprised with the said resin layer.   The tubular body for an image forming apparatus according to claim 2, wherein the average primary particle diameter of the surface-treated carbon black for the image forming apparatus is 30 nm or less.   4. The image forming apparatus according to claim 2, wherein a content of the surface-treated carbon black for the image forming apparatus with respect to 100 parts by mass of the resin included in the resin layer is 10 parts by mass or more and 30 parts by mass or less. Tubular body. A tubular body for an image forming apparatus according to any one of claims 2 to 4,
A support for supporting the tubular body for an image forming apparatus;
A tubular body unit for an image forming apparatus.   An image forming apparatus comprising the tubular body for an image forming apparatus according to any one of claims 2 to 4. 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 a developer containing toner to form a toner image;
An intermediate transfer belt which is a tubular body for an image forming apparatus according to any one of claims 2 to 4,
Primary transfer means for primarily transferring the toner image formed on the surface of the image carrier onto the outer peripheral surface of the intermediate transfer belt;
Secondary transfer means for secondary transfer of the toner image transferred to the outer peripheral surface of the intermediate transfer belt to a recording medium;
An image forming apparatus comprising: