JP2014164129A - Tubular body, tubular body unit, intermediate transfer body, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tubular body which has optimized constitution and structure and improved bending resistance and surface resistance while maintaining mechanical strength, and to stabilize transfer function of an image forming apparatus which uses an endless belt using the tubular body.SOLUTION: A tubular body (endless belt) is formed of a resin layer having a sea-island structure which comprises a sea part 10A including thermoplastic resin and an island part 10B including copolymer formed by copolymerizing thermoplastic resin with silicone resin and carbon black 10C. The tubular body is applied as an intermediate transfer belt of an image forming apparatus and a recording medium transfer conveyance belt.

Description

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

Conventionally, an image forming apparatus that obtains an image by electrostatically transferring a toner image via an intermediate transfer member is known (Patent Document 1).
Examples of the intermediate transfer member used in the image forming apparatus employing the intermediate transfer member method include polycarbonate resin (Patent Document 2), polyvinylidene fluoride resin (Patent Documents 3 and 4), and polyalkylene phthalate resin (Patent Document 5). An endless belt made of a thermoplastic resin layer and an endless belt made of a resin layer such as polyimide resin or wholly aromatic polyamide resin (Patent Document 6) have been proposed.
As an intermediate transfer member, an endless belt produced by extrusion molding of a polyetherimide resin (Patent Document 7) and a polyphenylene sulfide resin (Patent Document 8) as a thermoplastic resin has been proposed.
As an intermediate transfer member, an endless belt containing carbon black having a primary particle size of 20 nm or less has been proposed (Patent Document 9).
As an intermediate transfer member, an endless belt including a polyimide base material and polyetherimide / polysiloxane thereon has been proposed (Patent Document 10).
Further, a thermoplastic resin which is a block copolymer comprising a thermoplastic resin (A), a thermoplastic resin block unit (i) of the same type as the thermoplastic resin (A), and a polysiloxane block unit (ii). A conductive thermoplastic resin film containing (B) and conductive carbon black (C) has been proposed (Patent Document 11).

JP-A-62-206567 Japanese Patent Laid-Open No. 06-095521 Japanese Patent Laid-Open No. 5-200904 JP-A-6-228335 Japanese Patent Laid-Open No. 6-149081 Japanese Patent No. 2560727 JP 2000-137388 A JP 2004-94095 A JP 2010-250251 A JP 2010-237672 A JP 2011-26584 A

  An object of the present invention is to provide a tubular body excellent in folding resistance and surface resistance maintenance.

The above problem is solved by the following means. That is,
The invention according to claim 1
A tubular body having a resin layer having a sea-island structure composed of a sea part containing a thermoplastic resin and an island part containing a copolymer of a thermoplastic resin and a silicone resin and carbon black.

The invention according to claim 2
The tubular body according to claim 1, wherein the carbon black is carbon black having a volatile content rate of 0.4% or less up to 360 ° C.

The invention according to claim 3
The tubular body according to claim 1 or 2, wherein the copolymer contained in the island portion is a copolymer of a polyetherimide resin and a silicone resin.

The invention according to claim 4
The tubular body according to any one of claims 1 to 3, wherein a copolymerization ratio of the silicone resin in the copolymer of the thermoplastic resin and the silicone resin is 10% by mass or more and 30% by mass or less.

The invention according to claim 5
The tubular body according to any one of claims 1 to 4, wherein an average primary particle size of the carbon black is 25 nm or less.

The invention according to claim 6
The tubular body according to any one of claims 1 to 5, wherein the thermoplastic resin contained in the sea part is at least one selected from a polyetherimide resin and a polyphenylene sulfide resin.

The invention according to claim 7 provides:
A tubular body unit comprising: the tubular body according to any one of claims 1 to 6; 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.

The invention according to claim 8 provides:
An intermediate transfer member comprising the tubular member according to any one of claims 1 to 6.

The invention according to claim 9 is:
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;
An intermediate transfer member according to claim 8, wherein the toner image formed on the surface of the image carrier is transferred to the intermediate transfer member.
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;
Fixing means for fixing the toner image transferred to the recording medium;
An image forming apparatus.

According to the first aspect of the present invention, compared to the case where the thermoplastic resin, the thermoplastic resin, and the copolymer of the silicone resin are compatible, the resin layer containing carbon black is provided, and the folding resistance and the surface resistance are maintained. A tubular body having excellent properties is provided.
According to the invention which concerns on Claim 2, compared with the case where the volatile content rate of carbon black exceeds 0.4%, the tubular body excellent in the external appearance is provided.
According to the invention which concerns on Claim 3, compared with the case where the copolymer of polyetherimide resin and silicone resin is not included in an island part, the tubular body excellent in surface resistance maintenance property and an external appearance is provided.
According to the invention which concerns on Claim 4, compared with the case where the copolymerization ratio of the silicone resin in the copolymer of polyetherimide resin and silicone resin exceeds 30 mass%, a tubular body with high surface hardness is provided. .
According to the invention which concerns on Claim 5, compared with the case where the average primary particle diameter of carbon black exceeds 25 nm, the tubular body excellent in surface resistance maintenance property is provided.
According to the invention which concerns on Claim 6, compared with the case where the sea part contains the copolymer of polycarbonate resin, a polypolyetherimide, and a silicone resin, the tubular body excellent in mechanical strength is provided.

According to the seventh aspect of the invention, compared to a case where a tubular body having a resin layer containing carbon black is applied to a system in which a thermoplastic resin, a copolymer of a thermoplastic resin, and a silicone resin are compatible, it is more resistant to bending. A tubular body unit including a tubular body having excellent properties and surface resistance maintenance can be provided.
According to the inventions according to claims 8 and 9, compared to the case where a tubular body excellent in folding resistance and surface resistance maintenance is applied, an intermediate in which an image defect due to a failure due to bending or a reduction in resistance is suppressed. A transfer body and an image forming apparatus including the same can be provided.

It is a schematic perspective view which shows the tubular body which concerns on this embodiment. It is the elements on larger scale which show a part of resin layer which comprises the tubular body which concerns on this embodiment. 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, an embodiment which is an example of the present invention will be described in detail with reference to the drawings.

(Tubular body)
FIG. 1 is a schematic perspective view showing a tubular body according to this embodiment. FIG. 2 is a partially enlarged view showing a part of the resin layer constituting the tubular body according to the present embodiment.

As shown in FIG. 1, the tubular body 10 according to the present embodiment (hereinafter referred to as an endless belt) is formed, for example, in an endless manner, and is configured by, for example, a single layer body of a resin layer.
As shown in FIG. 2, the resin layer includes a sea part containing a thermoplastic resin, a copolymer of a thermoplastic resin and a silicone resin (hereinafter referred to as “silicone copolymer”), and an island part containing carbon black. And a resin layer having a sea-island structure composed of In FIG. 2, 10A indicates a sea portion, 10B indicates an island portion, and 10C indicates carbon black.

Here, conventionally, an endless belt composed of a resin layer in which carbon black is dispersed in a thermoplastic resin is known. However, the resistance of the endless belt having this configuration may be reduced due to carbonization of the resin due to discharge.
On the other hand, for the purpose of reducing the surface energy of the endless belt or suppressing the aggregation of carbon black, it is also known to form a resin layer by compatibilizing a silicone copolymer with a thermoplastic resin. However, the endless belt having this configuration becomes soft because the silicone structure enters the resin, and the mechanical strength may be insufficient.

On the other hand, the endless belt 10 according to the present embodiment is an endless belt excellent in folding resistance and surface resistance maintenance by being configured by the resin layer having the sea-island structure. Further, the endless belt is excellent in mechanical strength.
The reason for this is not clear, but is thought to be due to the following reasons.

Further, it is considered that the silicone copolymer has a high discharge resistance load that is less likely to cause carbonization due to electric discharge than the thermoplastic resin. In addition to this, it is considered that the silicone copolymer has higher carbon black dispersibility than the thermoplastic resin. That is, it is considered that the aggregation of carbon black hardly occurs. On the other hand, it is considered that the thermoplastic resin tends to have higher mechanical strength than the silicone copolymer. Further, when carbon black is added to the resin, the mechanical strength is improved, but the folding resistance is lowered.
For this reason, a thermoplastic resin having a high mechanical strength is configured as the sea part, while a silicone copolymer having a high discharge resistance load and a high carbon black dispersibility is configured as the sea part, and carbon black is formed on the island part. When the resin layer is constituted by the included sea-island structure, it is considered that the mechanical strength is maintained and the provision of the folding resistance and the surface resistance maintenance property are secured.

  From the above, it is considered that the endless belt 10 according to this embodiment is excellent in folding resistance and surface resistance maintenance. Moreover, it is thought that it is excellent also in mechanical strength.

  In addition, when the average primary particle size of carbon black is reduced (for example, when the particle size is 24 nm or less), the surface resistance maintenance property is improved. On the other hand, when the average primary particle size of the carbon black is reduced, the surface area is increased. For example, due to heat application during extrusion molding, decomposition of gas and functional groups (for example, acidic groups) attached to the surface of the carbon black. Gas is generated, and the appearance of the endless belt 10 (resin layer) is easily deteriorated due to voids. The endless belt 10 according to the present embodiment is such that even if the average primary particle size of carbon black is large (for example, the particle size is more than 24 nm and not more than 35 nm), it is easy to ensure surface resistance maintenance as described above. It is advantageous.

  Hereinafter, constituent materials and characteristics of the endless belt 10 according to the present embodiment will be described. In the following description, the reference numerals are omitted.

  The endless belt according to the present embodiment (resin constituting the endless belt) has a sea-island structure composed of a sea part including a thermoplastic resin and an island part including a silicone copolymer. And the carbon black is included in the inside of an island part. Moreover, the other additive may be included as needed.

  The sea-island structure is a structure in which two resins (thermoplastic resin and silicone copolymer) are mixed together in an incompatible state, and the sea part is a continuous phase made of one thermoplastic resin, and the sea part becomes the continuous phase. It means a structure in which a discontinuous phase composed of the other silicone copolymer existing in a suspended state is an island part.

In the sea-island structure, the diameter of the island part is preferably larger than the average primary particle size of the carbon black, specifically, for example, preferably 0.05 μm or more and 10 μm or less, and more preferably 0.1 μm or more and 2 μm or less.
The diameter of the island is measured by measuring the maximum diameter of 10 islands by preparing a sample (slice) of the resin layer by the cryo-tomome method and observing this sample with a transmission electron microscope (TEM). This is the average value.

The thermoplastic resin will be described.
Examples of the thermoplastic resin include polyester resins (for example, polybutylene terephthalate resin, polyethylene naphthalate resin, etc.), polyamide resins, polycarbonate resins, polysulfone resins, polyether sulfone resins, polyphenylene sulfide resins, polyimide resins, polyamideimide resins, Or polyetherimide resin etc. are mentioned.
Among these, as the thermoplastic resin, for example, polyetherimide resin and polyphenylene sulfide resin are preferable. When these resins are applied as the thermoplastic resin, the mechanical strength of the endless belt is increased, and deformation such as elongation and shrinkage is easily suppressed. As a result, when an endless belt is applied as an intermediate transfer member, occurrence of color misregistration is easily suppressed.
In addition, a thermoplastic resin may be used individually by 1 type, and may be used together 2 or more types.

The polyetherimide resin is a resin having a melt moldability containing, for example, an aliphatic, alicyclic or aromatic ether unit and a cyclic imide group as repeating units. Specific examples include those obtained by reacting an aromatic bis (ether dicarboxylic acid) and an organic diamine in an organic solvent at a heating temperature. For example, 2,2-bis [4- (2 , 3-dicarboxyphenoxy) phenyl] propane, 2,2-bis [4- (3,4-dicarboxyphenoxy) phenyl] propane, and 4,4′-diaminodiphenylmethane are mixed into a phenol / toluene mixed solvent. In addition, a polymer obtained by heating and refluxing, continuously removing water generated through the reaction by azeotropic distillation, and injecting the reaction product mixture into methanol to obtain a fibrous polymer may be mentioned.
Examples of commercially available polyetherimide resins include ULTEM 1000 series, 5000 series, and EXTEM VH1003 manufactured by SABIC Innovative Plastics.

The polyphenylene sulfide resin is, for example, a resin having a linear structure in which benzene rings and sulfur atoms are alternately bonded. In general, polyphenylene sulfide resin is obtained by polycondensing p-dichlorobenzene and sodium sulfide (sodium sulfide) at a high temperature and high pressure of 200 ° C. or higher and 290 ° C. or lower in, for example, an amide-based polar solvent (mainly NMP). It is a resin obtained by the technique.
Examples of commercially available products of polyphenylene sulfide resin include Torelina T1881 (manufactured by Toray Industries, Inc.) and Fortron 0220C9 (manufactured by Polyplastics).

  The content of the thermoplastic resin in the sea part is preferably 50% by mass or more and 95% by mass or less, preferably 60% by mass or more and 90% by mass or less, and more preferably 65% by mass or more and 85% by mass or less with respect to the total resin components. is there.

The silicone copolymer will be described.
The silicone copolymer is a copolymer of a thermoplastic resin and a silicone resin. The silicone copolymer may be any of a block copolymer, a graft copolymer, and a random copolymer. A silicone copolymer may be used individually by 1 type, and may be used together 2 or more types.

  Examples of the thermoplastic resin in the silicone copolymer include the same resin types as the thermoplastic resin constituting the sea part. In particular, from the viewpoint of moldability, the same resin as the thermoplastic resin applied to the sea part should be applied. Is good.

  On the other hand, examples of the silicone resin include dimethyl silicone resin, dimethyl ethyl silicone resin, diethyl silicone resin, diphenyl silicone resin, dimethyl phenyl silicone resin, and diethyl phenyl silicone resin. Among these, as the silicone resin, a dimethyl silicone resin is preferable from the viewpoint of maintaining surface resistance and suppressing deterioration of appearance.

Here, from the viewpoint of maintaining surface resistance and suppressing deterioration in appearance, the silicone copolymer is preferably a copolymer of a polyetherimide resin and a silicone resin.
Examples of the copolymer of polyetherimide resin and silicone resin include a reaction product of aromatic bis (ether anhydride), amine-terminated organosiloxane, and organic diamine.
Examples of commercially available copolymers of polyetherimide resin and silicone resin include SILTEM STM 1500, 1600, and 1700 manufactured by SABIC Innovative Plastics.

  The copolymerization ratio of the silicone resin of the silicone copolymer is preferably 10% by mass or more and 50% by mass or less, and more preferably 10% by mass or more and 30% by mass or less. In particular, when the copolymerization ratio of the silicone resin is 10% by mass or more and 30% by mass or less, the surface hardness of the endless belt is easily increased. As a result, when the endless belt is applied to the intermediate transfer member, the cleaning property is easily improved. The copolymerization ratio of the silicone resin is a mass ratio with respect to the entire copolymer.

  The content of the silicone copolymer in the island part is preferably 5% by mass or more and 50% by mass or less, preferably 10% by mass or more and 40% by mass or less, more preferably 15% by mass or more and 35% by mass with respect to the total resin component. It is as follows.

Carbon black will be described.
Examples of carbon black include oil furnace black, channel black, and acetylene black.

The average primary particle size of the carbon black is, for example, 35 nm or less, desirably 24 nm or less, desirably 16 nm or less. In particular, when the average primary particle size of carbon black is 25 nm or less, the conductive points of carbon black become fine and uniform, and resistance reduction due to discharge deterioration on the surface of the polyamide resin layer (endless belt 10) is easily suppressed.
From the above viewpoint, the average primary particle size of the carbon black is preferably as small as possible, but if the primary particle size is small, the bulk density becomes small and handling becomes difficult, and the surface area increases, so that the dispersion becomes thixotropic. Since it comes to show, it is good that it is 10 nm or more (desirably 12 nm or more).

The average primary particle size of carbon black is measured by the following method.
First, the obtained endless belt (resin layer) is cut with a microtome, a measurement sample having a thickness of 100 nm is collected, and this measurement sample is observed with a TEM (transmission electron microscope). Then, the diameter of 50 primary particles of carbon black is measured, and the average value is defined as the average primary particle diameter.

  Carbon black has a volatile content (volatile content up to 360 ° C.) of, for example, 0.45% or less, desirably 0.4% or less, and more desirably 0.3% or less. In particular, when the volatile content of carbon black is 0.4% or less, the appearance of the endless belt (resin layer) is hardly deteriorated due to voids.

The volatile content of carbon black indicates the amount of the air held on the carbon black surface and the decomposition of carboxyl groups and hydroxyl groups on the carbon black surface. And the volatile matter rate (volatile matter rate to 360 degreeC) of carbon black is measured by the following method.
Using a thermogravimetric analyzer (DTG-60, manufactured by Shimadzu Corporation), the mixture is heated at 120 ° C. for 15 minutes in a nitrogen atmosphere to evaporate water, and then heated to 500 ° C. at a rate of 20 ° C./min. The mass after 120 minutes at 120 ° C. (expressed as 120 ° C. mass) and the mass when heated to 360 ° C. (expressed as 360 ° C. mass) were examined, and the formula: (120 ° C. weight−360 ° C. weight) / 120 ° C. Calculated by weight × 100 to determine the volatile content of carbon black.

  The pH of the carbon black is, for example, preferably 5 or more, desirably 7.0 or more and 11.0 or less, and more desirably 8 or more and 10 or less.

  The pH of carbon black refers to the pH (logarithmic value of hydrogen ion concentration) measured with respect to a muddy substance obtained by boiling carbon black in water and removing the supernatant after cooling according to JIS K6221-1982. . This is related to the amount of oxygen-containing functional groups on the carbon black surface (functional groups such as carboxylic acid, hydroxy acid, lactone, and quinoid), and it is thought that the lower the pH, the more acidic surface functional groups ( Edited and published by Carbon Black Association, “Carbon Black Handbook”, 1995, see).

  The content of carbon black is, for example, preferably 15% by mass or more and 30% by mass with respect to all resin components, and preferably 20% by mass or more and 25% by mass or less.

Other additives will be described.
As other additives, for example, antioxidants for preventing thermal deterioration of the polyamide resin layer, lubricants for improving fluidity, and the like, particularly known additives blended in an endless belt of an image forming apparatus Is mentioned.

Next, the characteristics of the endless belt according to the present embodiment will be described.
The endless belt 10 (resin layer) according to the present embodiment has a surface resistivity of 7 logΩ / □ or more and 13 logΩ when measured by applying a voltage of 100 V in a normal temperature and normal humidity (temperature 22 ° C., humidity 55 RH%) environment. In particular, when the endless belt 10 is applied as an intermediate transfer belt, it is preferably 8 logΩ / □ or more and 12 logΩ / □ or less, and when the endless belt is applied as a recording medium conveyance transfer belt, It is good that they are 9 log Ω / □ or more and 13 log Ω / □ or less.
In addition, this surface resistivity is a measured value when applying a voltage of 100 V in a normal temperature and normal humidity (temperature 22 ° C., humidity 55 RH%) environment.

The endless belt 10 (resin layer) according to this embodiment has a surface resistivity and a normal temperature and normal humidity (temperature) measured by applying a voltage of 100 V in a normal temperature and normal humidity (temperature 22 ° C., humidity 55 RH%) environment. The difference from the surface resistivity when measured by applying a voltage of 1000 V under an environment of 22 ° C. and humidity of 55 RH% is preferably 1.0 logΩ / □ or less.
The endless belt 10 (resin layer) 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). The difference from the surface resistivity when measured by applying a voltage of 100 V under an environment of (° C., humidity 85 RH%) 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 measured by using a microammeter R8340A manufactured by Advantest, and the surface resistivity is obtained from the surface resistance value obtained from the current value.

Hereinafter, the manufacturing method of the endless belt according to the present embodiment will be described.
First, for example, a silicone copolymer, carbon black, and, if necessary, other additives are kneaded and mixed in desired amounts to obtain carbon black-containing resin pellets. Then, the carbon black-containing resin pellets, the thermoplastic resin, and other additives as necessary are kneaded and mixed in desired amounts to obtain resin pellets.

  Next, the pellets of the obtained resin composition are used and extruded into a cylindrical shape using an extruder and cooled and solidified to obtain a cylindrical molded body. In addition, the silicone copolymer, carbon black, and other additives as required are kneaded and mixed in the respective desired amounts to obtain carbon black-containing resin pellets, and then the resin pellets and the respective objectives. They may be mixed in the blending amount, extruded into a cylindrical shape using an extruder, and cooled and solidified to obtain a cylindrical molded body.

In order to obtain a cylindrical molded body, for example, the resin composition pellets are melt extruded into a cylindrical shape and taken out while being stretched, and the inner peripheral surface and the outer peripheral surface of the resin composition extruded into the cylindrical shape are taken. This is done by cooling. At this time, it is preferable to replace the resin composition flow path in the extruder with an inert gas.
By using extrusion molding, the process is simple and inexpensive compared to the casting method, and molding is realized.

  And the obtained cylindrical molded object is cut | disconnected to the target width | variety, and an endless belt is obtained.

The endless belt according to the present embodiment described above has been described in the form of a single-layered resin layer. However, if the endless belt has the resin layer, the endless belt may be formed of a laminate of two or more layers. Good.
Specifically, for example, the endless belt according to the present embodiment is composed of a laminate of a base material layer and a surface layer (surface release layer) on the outer peripheral surface thereof, and at least one of the base material layer and the surface layer. The resin layer may be applied. However, when the resin layer is applied as a surface layer, a release material (for example, a fluorine compound (fluorine resin or particles thereof) or the like) may be blended.
Of course, an intermediate layer may be provided between the base material layer and the surface layer, or the base material layer itself may be composed of a laminate of two or more layers.

  The endless belt 10 according to the present embodiment can be applied to, for example, a belt for an image forming apparatus (for example, an intermediate transfer belt or a recording medium conveyance transfer belt).

(Tubular body unit)
FIG. 3 is a schematic perspective view showing the tubular body unit according to the present embodiment.
The tubular body unit 130 (hereinafter referred to as an endless belt unit) according to the present embodiment includes the endless belt 10 according to the present embodiment as illustrated in FIG. 3. For example, the endless belt 10 is opposed to the endless belt 10. The tension is applied by the drive roll 131 and the driven roll 132 that are arranged (hereinafter, sometimes referred to as “stretching”).
Here, in the case where the endless belt 10 is applied as an intermediate transfer member, the endless belt unit 130 according to the present embodiment uses the endless belt 10 as a roll for stretching the endless belt 10 to transfer the toner image on the surface of the photoreceptor (image holding member). A roll for primary transfer onto the recording medium 10 and a roll for secondary transfer of the toner image transferred onto the endless belt 10 onto the recording medium are disposed.
The number of rolls around which the endless belt 10 is stretched is not limited, and may be arranged according to the usage mode. The endless belt unit 130 having such a configuration is used by being incorporated in the apparatus, and rotates in a state where the endless belt 10 is stretched along with the rotation of the drive roll 131 and the driven roll 132.

(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. A developing unit that forms a toner image; a transfer unit that transfers the toner image to a recording medium; and a fixing unit that fixes the toner image to the recording medium. The transfer unit is an endless belt according to the present embodiment. Is provided.

  Specifically, in the image forming apparatus according to the present embodiment, for example, the transfer unit transfers the toner image formed on the intermediate transfer member and the image holding member to the intermediate transfer member. And a secondary transfer unit that secondarily transfers the toner image to a recording medium, and the endless belt according to the present embodiment as the intermediate transfer member.

  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 holding body are conveyed by the paper transfer body. And a transfer unit for transferring to a recording medium, and the recording medium transfer body includes the endless belt 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. 4 is a schematic configuration diagram illustrating the image forming apparatus according to the embodiment.

  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 the four image holding members 101a to 101d 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 to form a tubular body unit 107b. With the support rolls 106a to 106d, the drive 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 rolls 105a to 105d. Can be moved in the direction of arrow A. A portion where the primary transfer rolls 105a to 105d are in contact with the image carriers 101a to 101d via the intermediate transfer belt 107 is a primary transfer portion, and a 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 multi-color image forming apparatus 100 having this configuration, the image carrier 101a rotates in the direction of the arrow C, and the surface is charged by the charging device 102a, and then the first color static light is exposed by the exposure device 114a such as laser light. An electrostatic latent image is formed. The formed electrostatic latent image is developed (visualized) with 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 rollers 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 / or pressurization, and then discharged outside the apparatus.

  The 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 applied in a superimposed manner.

-Exposure device-
The exposure devices 114a to 114d are not particularly limited. For example, a light source such as a semiconductor laser light, an LED (Light Emitting Diode) light, or a liquid crystal shutter light is provided on the surface 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 contact or non-contact with a brush or roller or the like 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 secondary transfer roll 109 includes a core layer, an intermediate layer, and a coating layer covering 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.

-Opposite 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 opposed roll 108 and the shaft of the secondary transfer roll 109. Instead of applying a voltage to the shaft 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. “Part” or “%” means “part by mass” or “% by mass” unless otherwise specified.

[Examples 1 to 11 and Comparative Examples 1 to 16]
Resins and carbon black (indicated as CB) having the composition shown in Table 1 were mixed using a Henschel mixer (FM10C manufactured by Nippon Coke). The mixed composition was melt kneaded with a twin-screw extrusion melt kneader (L / D60 (manufactured by Parker Corporation)) at the kneading temperature shown in Table 1 and extruded into a string shape through a hole of φ5, and placed in a water tank. After cooling and solidification, the cooled and solidified string-like material was inserted into a pelletizer and cut with a cut size of about 5 mm in length to obtain a CB-containing resin pellet.

  Next, the CB-containing resin pellets and the resin having the compositions shown in Tables 2 to 4 were mixed using a Henschel mixer (FM10C manufactured by Nippon Coke). The mixed composition was put into a single screw melt extruder (L / D24, melt extrusion apparatus (manufactured by Mitsuba Seisakusho)) set to the extrusion temperature described in Tables 2 to 4, and the annular die and nipple were melted while melting. Extruded cylindrically from the gap. The inner peripheral surface of the extruded cylindrical molten resin is brought into contact with a cooling mold (temperature 30 ° C.), cooled, and then cut into a target width by a cutting machine, and the outer diameter φ160 × 232 × about 100 μm. An endless belt was obtained.

[Evaluation]
The following evaluation was performed on the endless belt obtained in each example. The results are shown in Tables 5-7.

(Confirmation of sea-island structure)
A small piece sample was cut out from the endless belt obtained in each example, and the sample cross-section block was prepared by embedding and solidifying in a resin for electron microscope and using a microtome. The cross-section obtained by vapor-depositing Pt was observed with an FE-SEM (JSM-6700F manufactured by JEOL Ltd., acceleration voltage: 5 kV / 10 kV). This confirmed the presence or absence of a sea-island structure. In the case of the sea-island structure, the presence of carbon black was confirmed on the island. In the endless belts obtained in some comparative examples (Comparative Examples 1-8, 15-16), the resin was mixed in a compatible state, and the sea-island structure could not be confirmed.

(Folding resistance (MIT))
A strip-shaped sample of 15 mm × 150 mm was cut out from the endless belt obtained in each example, and the load was 1 kgf, and the number of times until breakage occurred was measured using an MIT tester apparatus (manufactured by Ueshima Seisakusho).

(appearance)
The appearance of the endless belt obtained in each example was visually observed.
The evaluation criteria are as follows.
A: No defect B: Small protrusion / recessed C: Large protrusion / recessed D: Severe protrusion / recessed

(Surface resistivity / maintainability)
About the endless belt obtained in each example, the surface resistivity was measured by the method described, and its maintainability was evaluated.
Specifically, the endless belt obtained in each example is incorporated as an intermediate transfer member in DocuPrint CP200W manufactured by Fuji Xerox Co., Ltd., and a halftone image (magenta density of 30%) in a low-temperature and low-humidity environment of 10 ° C. and 15% RH. Was continuously output on A5 vertical paper. The secondary transfer voltage at this time was 5.6 kV. The surface resistivity of the endless belt before and after this evaluation was measured, and the difference between the common logarithm of the surface resistivity before evaluation and the common logarithm of the surface resistivity after evaluation was determined. This difference was evaluated as surface resistance maintenance. The change in the surface resistivity as the surface resistance maintainability is required to be 0.6 or less, preferably 0.3 or less.
The evaluation criteria are as follows.
A: Difference in common logarithm of surface resistivity is less than 0.3 B: Difference in common logarithm of surface resistivity is less than 0.6 C: Difference in common logarithm of surface resistivity is less than 1.1 D: Difference in common logarithm of surface resistivity is 1.1 or more

(Cleanability)
The endless belt obtained in each example was incorporated into DocuPrint CP200W manufactured by Fuji Xerox Co., Ltd. as an intermediate transfer member, and a low-density image (5% magenta density) was continuously printed on A4 vertical paper in an environment of 22 ° C. and 55% RH. After output, three sheets of A4 vertical paper on which a halftone image (magenta density of 40%) is formed only in the first half of the paper conveyance direction are output, and the toner stains on the non-image area of the second half of the third paper are visually observed. Observed.
Also, if there is no toner contamination, observe the surface of the endless belt, observe the degree of toner adhesion, and check for the presence of toner filming (a phenomenon in which the toner is crushed and accumulated in the form of a film on the endless belt surface). did.
The evaluation criteria are as follows.
A: Image: No toner stain / endless belt surface: No toner filming B: Image: No toner stain / endless belt surface: Toner filming C: Image: Toner stain D: Image: Severe toner stain

(Color shift)
The endless belt obtained in each example is incorporated in DocuPrint CP200W manufactured by Fuji Xerox Co. as an intermediate transfer member, and green belt-like images are arranged at intervals in an environment of 22 ° C. and 55% RH (caterpillar pattern) Was output to A4 vertical paper, and the occurrence of color misregistration was visually evaluated.
The evaluation criteria are as follows.
A: No color shift of the band-shaped image B: Color shift of less than 0.2 mm of the band-shaped image C: Color shift of less than 0.5 mm of the band-shaped image D: Color shift of 0.5 mm or more of the band-shaped image

  From the above results, it can be seen that in this example, better results were obtained for both the foldability and the evaluation of the surface resistivity maintenance than the comparative example.

-Resin-
SILTEM 1700: polyetherimide resin-silicone resin copolymer “(SABIC Innovative Plastics)”, silicone resin copolymer ratio 10 mass%
SILTEM 1600: polyetherimide resin-silicone resin copolymer “(SABIC Innovative Plastics)”, silicone resin copolymer ratio 30 mass%
SILTEM 1500: polyetherimide resin-silicone resin copolymer “(manufactured by SABIC Innovative Plastics)”, (silicone resin copolymer ratio 50 mass%
Torelina T1881: Polyphenylene sulfide resin “Torelina T1881 (manufactured by Toray Industries, Inc.)”
・ Ultem 1000V: Polyetherimide resin “Ultem 1000V (manufactured by SABIC Innovative Plastics)”
-Lexan 131: Polycarbonate resin (SABIC Innovative Plastics)

-Carbon black-
Denka black granular product: carbon black “Denka black granular product (manufactured by Denki Kagaku Kogyo Co., Ltd.)”, primary average particle size 35 nm, volatile content 0.00%
# 4000B: Carbon black “# 4000B (manufactured by Mitsubishi Chemical)”, primary average particle size 24 nm, volatile content rate up to 360 ° C. 0.17%
-Monark 880: Carbon black "Monark 880 (manufactured by Cabot)", primary average particle diameter 16 nm, volatile content ratio up to 360 ° C 0.43%

10 Tubular body (endless belt)
101a to 101d Image holding members 102a to 102d Charging devices 103a to 103d Developing devices 104a to 104d Image holding member cleaning devices 105a to 105d Primary transfer rolls 106a to 106d Support roll 107 Intermediate transfer belt 107b Tubular unit (endless belt unit)
108 Counter roll 109 Secondary transfer roll 110 Fixing device 111 Drive roll 112 Intermediate transfer belt cleaning blade 113 Intermediate transfer belt cleaning brushes 114a to 114d Image exposure device 115 Recording medium 116 Secondary transfer belt

Claims (9)

  A tubular body having a resin layer having a sea-island structure composed of a sea part containing a thermoplastic resin and an island part containing a copolymer of a thermoplastic resin and a silicone resin and carbon black.   The tubular body according to claim 1, wherein the carbon black is carbon black having a volatile content rate of 0.4% or less up to 360 ° C.   The tubular body according to claim 1 or 2, wherein the copolymer contained in the island portion is a copolymer of a polyetherimide resin and a silicone resin.   The tubular body according to any one of claims 1 to 3, wherein a copolymerization ratio of the silicone resin in the copolymer of the thermoplastic resin and the silicone resin is 10% by mass or more and 30% by mass or less.   The tubular body according to any one of claims 1 to 4, wherein an average primary particle size of the carbon black is 25 nm or less.   The tubular body according to any one of claims 1 to 5, wherein the thermoplastic resin contained in the sea part is at least one selected from a polyetherimide resin and a polyphenylene sulfide resin.   A tubular body unit comprising: the tubular body according to any one of claims 1 to 6; 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.   An intermediate transfer member comprising the tubular member according to any one of claims 1 to 6. 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;
An intermediate transfer member according to claim 8, wherein the toner image formed on the surface of the image carrier is transferred to the intermediate transfer member.
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;
Fixing means for fixing the toner image transferred to the recording medium;
An image forming apparatus.