JP2012230157A - Component of intermediate transfer belt and manufacturing method thereof, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a component of an intermediate transfer belt that uses a thermoplastic resin, and prevents toner fusion even after image output for a long period.SOLUTION: A component of an intermediate transfer belt is formed by subjecting a resin composition containing at least a thermoplastic resin and a conductive agent to fusion-extrusion molding so as to provide an endless belt shape, irradiating the outer peripheral surface of the belt with an electron beam having an acceleration voltage of 10-70 kV, and crosslinking an oligomer component derived from the thermoplastic resin on the surface layer of the belt with an electron beam.

Description

  The present invention relates to an intermediate transfer belt member used in an electrophotographic image forming apparatus, a manufacturing method thereof, and an image forming apparatus.

  Conventionally, in an electrophotographic image forming process in a copying machine, a printer, etc., first, the surface of a photosensitive member (latent image holding member) is uniformly charged, and an image is projected onto the photosensitive member from an optical system. An electrostatic latent image is formed by erasing the charged portion of the toner, and then supplying toner to the electrostatic latent image to form a toner image by electrostatic adhesion of the toner. A method of printing by transferring to a recording medium such as photographic paper is employed.

  In an electrophotographic color copying machine, printing is basically performed according to the above process, but in the case of color printing, the color tone is reproduced using toners of four colors, magenta, yellow, cyan, and black. However, a process for obtaining a required color tone by superimposing these toners at a predetermined ratio is necessary, and several methods have been proposed to perform this process, and among these, an intermediate transfer member was used. An intermediate transfer method is common.

  This intermediate transfer system is provided with a belt-like intermediate transfer member that temporarily transfers and holds a toner image on a photosensitive member, and a magenta toner image, a yellow toner image, a cyan toner image, and a cyan toner image formed by four photosensitive members, respectively. A black toner image is directly or indirectly transferred onto an intermediate transfer member to form a color image on the intermediate transfer member, and the color image is transferred onto a recording medium such as paper.

  Here, as a material used for the intermediate transfer member, two kinds of resins, that is, a curable resin and a thermoplastic resin can be given. Recently, among these, an intermediate transfer belt member manufactured using a thermoplastic resin has been used as one having excellent bending resistance (for example, see Patent Document 1).

  However, when image output is performed for a long time in such an image forming apparatus using an intermediate transfer belt member made of a thermoplastic resin as an intermediate transfer member, an image defect caused by toner fusion to the surface of the intermediate transfer belt member May occur.

  The present invention has been made in view of the above-described problems in the prior art, and is an intermediate transfer belt member using a thermoplastic resin, in which toner fusion does not occur even during long-time image output. Another object of the present invention is to provide an image forming apparatus using the intermediate transfer belt member.

  The inventors investigated the cause of toner fusing on the surface of the intermediate transfer belt member when an image is output for a long time in an image forming apparatus using the intermediate transfer belt member made of thermoplastic resin. It was found that the oligomer component derived from the plastic resin (Mw = about 500 to 10,000) deteriorates the stain resistance against the toner. That is, in the manufacturing process of the intermediate transfer belt member, when kneading and dispersing the thermoplastic resin and the conductive agent in order to adjust to an appropriate electrical resistance as the intermediate transfer member, or when molding the resin composition with an extruder, The molecular chain of the plastic resin is cut by heat and shearing force, and is present as an oligomer component on the belt surface after the belt is formed. As a result, toner fusion is caused in the intermediate transfer belt member.

  Here, in order to suppress the formation of such oligomer components, techniques for controlling the amount of water in the resin or adding a deterioration (oxidation) inhibitor or the like are known. However, even if the amount of water in the resin is controlled or an antioxidant is added to suppress hydrolysis of the ester, hydrolysis of the ester bond cannot be completely suppressed. In addition, since the intermediate transfer belt member requires high electrical characteristics, a conductive agent such as carbon black must be uniformly and finely dispersed in the resin, so it is necessary to perform kneading for a long time at a high temperature. Since the oligomer component is more easily generated, it was more difficult to suppress the oligomer component. In addition, a technique is generally known in which crosslinking treatment is performed by electron beam irradiation in order to compensate for a decrease in physical properties due to molecular chain cleavage even after the oligomer component is formed. However, in the conventional method, the oligomer component can be recombined by cross-linking treatment by electron beam irradiation after molding. However, the molecular chain breakage of the thermoplastic resin occurs due to the simultaneously irradiated electron beam, and the intermediate transfer belt member There was a problem that the physical properties deteriorated.

Based on the knowledge that the oligomer component is unevenly distributed on the surface layer of the intermediate transfer belt member, the inventors have intensively studied to solve this problem and have achieved the present invention.
In JP 2007-65587 A, a resin composition obtained by blending a thermoplastic resin, a conductive agent, and a crosslinking agent is extruded into a belt shape, and then subjected to crosslinking treatment by electron beam irradiation. Although a transfer belt is disclosed, it is intended to obtain rigidity (folding resistance, set resistance) equivalent to that of a thermosetting resin by crosslinking treatment by electron beam irradiation. The configuration is different.

  That is, the present invention provided in order to solve the above-mentioned problems is to melt and extrude a resin composition containing at least a thermoplastic resin and a conductive agent into an endless belt shape, and then to an electron having an acceleration voltage of 10 to 70 kV on the outer peripheral surface of the belt. The intermediate transfer belt member is formed by irradiating a wire and electron beam cross-linking the oligomer component derived from the thermoplastic resin on the belt surface layer.

  Further, the present invention provided to solve the above problems includes a melt extrusion process for forming a resin composition containing at least a thermoplastic resin and a conductive agent into an endless belt shape, and an acceleration voltage of 10 to 70 kV on the outer peripheral surface of the belt. And an electron beam irradiation step of crosslinking the oligomer component derived from the thermoplastic resin on the belt surface layer with an electron beam, and a method for producing an intermediate transfer belt member.

  Further, the present invention provided to solve the above-described problems includes at least an electrostatic latent image forming unit for forming an electrostatic latent image on the image carrier, and an electrostatic latent image formed on the image carrier. Developing means for converting the toner image into a toner image using toner, primary transfer means for transferring the toner image on the image carrier onto the intermediate transfer member, and transferring the toner image on the intermediate transfer member onto the recording medium An image forming apparatus comprising: a secondary transfer unit that performs fixing; and a fixing unit that fixes a toner image on the recording medium, wherein the intermediate transfer member includes at least a thermoplastic resin and a conductive agent. An intermediate transfer belt obtained by melt-extrusion molding into an endless belt shape and then irradiating the outer peripheral surface of the belt with an electron beam having an acceleration voltage of 10 to 70 kV to crosslink the oligomer component derived from the thermoplastic resin on the belt surface layer. It is a member An image forming apparatus.

  According to the intermediate transfer belt member of the present invention, the outer peripheral surface of the extruded endless belt is irradiated with an electron beam having an acceleration voltage of 10 to 70 kV, and the oligomer component derived from the thermoplastic resin unevenly distributed on the belt surface layer is subjected to electron beam crosslinking. Therefore, it is possible to recombine (fix) the oligomer component on the surface layer of the belt without deteriorating the physical properties of the intermediate transfer belt member, and it has excellent stain resistance against toner. Therefore, when the intermediate transfer belt member of the present invention is applied to an image forming apparatus, the toner is fused to the surface of the intermediate transfer belt member without deterioration of the belt characteristics even when image output is performed for a long time. And high-quality image output can be obtained.

FIG. 3 is an external view showing a configuration of an intermediate transfer belt member according to the present invention. It is a figure which shows the relationship between the acceleration voltage of an electron irradiation apparatus, an arrival depth, and absorbed dose. It is sectional drawing which shows the structural example (1) of the electrophotographic formation apparatus which concerns on this invention. It is sectional drawing which shows the structural example (2) of the electrophotographic formation apparatus which concerns on this invention. FIG. 5 is a cross-sectional view illustrating a configuration of a tandem developing device used in the electrophotographic forming apparatus in FIG. 4. 6 is a diagram showing a GPC analysis result of a THF eluting component on a belt surface in Test Example 1. FIG.

The configuration of the intermediate transfer belt member according to the present invention will be described below.
FIG. 1 is an external view showing a configuration of an intermediate transfer belt member according to the present invention.
The intermediate transfer belt member 1 is a substantially cylindrical endless belt, but has flexibility as a belt and can be freely deformed. FIG. 1 shows a state in which the entire shape of the outer peripheral surface of the belt is formed in an oval shape over two rolls.

  The dimensions of the intermediate transfer belt member 1 are 100 to 300 mm in outer diameter and 100 to 300 mm in width W when it is cylindrical. The thickness t of the intermediate transfer belt member 1 is 50 to 200 μm.

  Here, the intermediate transfer belt member 1 is obtained by melting and extruding a resin composition containing at least a thermoplastic resin and a conductive agent into an endless belt shape, and then forming 10 to 70 kV, more preferably 10 to 50 kV on the outer peripheral surface of the belt. An electron beam of low acceleration voltage is irradiated to crosslink the oligomer component derived from the thermoplastic resin on the belt surface layer by electron beam crosslinking.

The resin composition used in the present invention is preferably such that, when melt-extruded into the endless belt shape, the belt molded product has predetermined electrical characteristics and mechanical characteristics as an intermediate transfer belt member. It is preferable that the tensile elastic modulus is 1500 Mpa or more and less than 4000 Mpa, and the volume resistivity is 1.0 × 10 ⁶ Ω · cm or more and less than 1.0 × 10 ¹² Ω · cm (Condition A).

Here, the measuring method of the tensile elasticity modulus and volume resistivity of a belt molding is as follows, for example.
[Measurement method of tensile modulus]
In the present invention, the tensile elastic modulus is obtained by punching the belt molded product with a dumbbell shape of JIS K-7127 with a super dumbbell cutter SDMK-1000-D (manufactured by Dumbbell Co., Ltd.) to produce a dumbbell sample. The value of the tensile modulus of the belt was determined from the strain-stress curve using -X (manufactured by Shimadzu Corporation).

[Measurement method of volume resistivity]
The volume resistivity in the present invention is a value measured after 10 seconds using a Hiresta UP MCP-HT450 type (manufactured by Dia Instruments Co., Ltd.) under an environment of a temperature of 23 ° C. and a humidity of 65% with an applied voltage of 250V. Value.

  In addition, as the thermoplastic resin constituting the resin composition, a material generally used for an intermediate transfer belt member can be used. For example, the thermoplastic resin used in the present invention is a polymer having an ester bond, that is, a polyester resin, a polycarbonate resin (PC) which is a polymer having a carbonate bond, a polyvinylidene fluoride resin (PVDF) having an ethylene chain, a poly Any of phenyl sulfide (PPS) resin is good to be included. These resins may be used alone or in combination with the polyester-based resin described above.

  Moreover, it is preferable that the thermoplastic resin used by this invention is a material from which the said resin composition satisfy | fills the said conditions A among these, and a polyester-type resin is suitable. Specific examples of the polyester-based resin include polyalkylene naphthalate resins and polyalkylene terephthalate resins. Among these, polyalkylene naphthalate resins include polyethylene naphthalate (PEN) resins and polyalkylene naphthalate resins. Butylene naphthalate (PBN) resin or the like can be suitably used. As the polyalkylene terephthalate resin, polyethylene terephthalate (PET) resin, glycol-modified PET (PETG) resin or polybutylene terephthalate (PBT) resin can be suitably used. Furthermore, a polyester elastomer (TPEE) can be used. These polyester resins may be used alone or in combination of two or more.

  The conductive agent used in the present invention is conductive fine particles having an average primary particle diameter of 5 to 50 nm. Further, the material constituting the conductive fine particles serving as a conductive agent is not particularly limited, but for example, carbon black, graphite, natural graphite, artificial graphite, tin oxide, titanium oxide, zinc oxide, nickel, copper It is preferable to include any one or more.

[Dispersion of conductive fine particles]
Dispersion of the conductive fine particles in the resin material includes a step of wetting the conductive fine particles in the resin material and a step of finely dispersing the conductive fine particles by a shearing force.

  Among these, in the process of wetting the conductive fine particles to the resin material, the wettability between the resin material and the conductive fine particles is improved by improving the melt viscosity of the resin, or the compatibility between the resinous material and the conductive fine particles is improved. The method of letting you do is mentioned.

  In the present invention, the conductive fine particles are dispersed by kneading the resin and the conductive fine particles while applying heat. When dispersing, the temperature is preferably equal to or higher than the glass transition temperature (Tg) of the resin, and more preferably kneaded at a temperature at which the resin becomes more molten.

  In general, when conductive fine particles are melt-kneaded into a thermoplastic resin, a high shear force is applied to the aggregated conductive fine particles to break down and refine the conductive fine particles, and uniformly disperse the conductive fine particles into the molten resin. Let At this time, if the melt viscosity is lowered too much, the wettability is further improved, but the problem is that the shearing force for finely dispersing the conductive fine particles is lowered. In the present invention, it is preferable to use a disperser capable of generating a high shear force with a low melt viscosity in order to deal with such problems.

  Examples of such a kneader that generates a high shear force include those using a stone mortar mechanism, and those in which a kneading disk with high shear force is introduced into a screw element by the same direction twin screw extruder. In addition, there are examples such as a pressure kneader that does not require a high shearing force and can achieve dispersion over time, and that a special mixing element is used in a single screw extruder.

  As a method for improving the compatibility between the resin material and the conductive fine particles, there are a method for treating the surface of the conductive fine particles, a method for adding a dispersing agent for improving the wettability between the resin material and the conductive fine particles, an ionic conductive agent, and the like. Can be mentioned. Examples of the surface treatment of the conductive fine particles include a method of treating in advance before the dispersion step, and a method of finely dispersing the surface treatment simultaneously in the dispersion step. Further, there is a method in which the resin material is roughly pulverized to a volume average particle diameter of about 100 μm to 1000 μm at room temperature or in a frozen state, mixed with conductive fine particles, and then melt-kneaded.

  The blending amount of the conductive agent is usually 100 parts by weight or less, for example, 1 to 100 parts by weight, particularly 1 to 80 parts by weight, especially 5 to 50 parts by weight with respect to 100 parts by weight of the resin component. In the present invention, it is particularly preferable to use carbon black as a conductive agent and mix it with 5 to 30 parts by weight with respect to 100 parts by weight of the resin component.

  Moreover, it is preferable that the said resin composition contains a crosslinking agent. The cross-linking agent used in the present invention is not particularly limited as long as it can cause a cross-linking reaction by irradiation with an electron beam, but is preferably triallyl isocyanurate, triallyl cyanurate, trimeta. Any of allyl isocyanurate and diallyl monoglycidyl isocyanurate, or a mixture of any two or more of these may be mentioned.

  A suitable blending amount of the crosslinking agent is 0.3 to 15 parts by weight, preferably about 0.5 to 5 parts by weight with respect to 100 parts by weight of the resin component.

  In addition, other functional components can be appropriately added to the intermediate transfer belt member 1 of the present invention as long as the effects of the present invention are not impaired. For example, various fillers, coupling agents, antioxidants A lubricant, a surface treatment agent, a pigment, an ultraviolet absorber, an antistatic agent, a dispersant, a neutralizing agent, a foaming agent, a crosslinking agent, and the like can be appropriately blended. Furthermore, you may color by adding a coloring agent.

Next, a method for manufacturing the intermediate transfer belt member according to the present invention will be described.
In the production of the intermediate transfer belt member of the present invention, a melt extrusion molding step of forming a resin composition containing at least a thermoplastic resin and a conductive agent into an endless belt shape (for example, a cylindrical shape), and an outer peripheral surface of the belt (cylinder) And an electron beam irradiation step of irradiating an electron beam with an acceleration voltage of 10 to 70 kV, more preferably 10 to 50 kV to crosslink the oligomer component derived from the thermoplastic resin on the surface layer of the belt (cylinder). To do.

  First, in the melt extrusion molding step, the resin composition containing the above-described various components is kneaded, heated and extruded into a cylindrical shape, and cut into a predetermined width. Thus, an endless belt shape having a predetermined dimension (outer diameter, width, thickness) is formed (temporarily referred to as a molded belt). The extrusion molding may be carried out in accordance with a conventional method, and is not particularly limited. Examples of the extrusion molding include an extrusion molding method in which a belt material is extruded from an annular die and a belt molding, and an inflation molding method.

  In this melt extrusion molding process, when a thermoplastic resin and a conductive agent are kneaded and dispersed, or when a resin composition is molded with an extruder, the molecular chain of the thermoplastic resin is cut by heat and shearing force, and the surface layer of the molded belt The oligomer component is formed in In the state where the oligomer component remains, the stain resistance against the toner is lowered. Therefore, in the present invention, the improvement is made in the electron beam irradiation process which is the next process.

  That is, in the electron beam irradiation process, for example, a metal cylinder is inserted into the inner diameter portion of an extruded molding belt, and while rotating this cylinder, from an irradiation device disposed on both sides in the axial direction of the metal cylinder Irradiate an electron beam. There is no restriction | limiting in particular about this electron beam irradiation apparatus, A commercially available apparatus can be used suitably.

  Here, if the acceleration voltage at the time of electron beam irradiation is normal electron beam crosslinking conditions (for example, 150 kV), the oligomer component generated in the melt extrusion molding process can be immobilized, but the molecular chain of the thermoplastic resin is also cut. As a result, the belt characteristics as the intermediate transfer belt member are deteriorated.

  Therefore, in the present invention, the depth at which the electron beam reaches from the resin surface (reach depth) is proportional to the acceleration of the electron beam as shown in FIG. Only the surface layer of the outer peripheral surface of the forming belt is irradiated with an electron beam at an ultra-low acceleration voltage of 70 kV or less, which is much lower than that at the time of wire crosslinking (for example, 150 kV).

  Specifically, the acceleration voltage of the electron beam at this time is set to 10 to 70 kV, and the region where the electron beam reaches (reach depth) is a region from the outer peripheral surface of the forming belt to a depth of about 5 to 60 μm. Preferably, the acceleration voltage of the electron beam is 10 to 50 kV, and the region where the electron beam reaches (reach depth) is a region from the outer peripheral surface of the forming belt to a depth of about 5 to 30 μm. If the acceleration voltage is less than 10 kV, the electron beam reach depth is less than 5 μm, and the electron beam cross-linking of the oligomer component on the belt surface layer is insufficient, and the stain resistance against the toner is not sufficiently improved. On the other hand, if the acceleration voltage exceeds 70 kV, the amount of electron beam irradiation (absorbed dose) on the belt surface layer increases and the molecular chain of the thermoplastic resin is broken, which is not suitable. Thus, when the molecular cutting in the depth direction of the belt is advanced, the breaking elongation of the belt is remarkably lowered.

  Further, the irradiation amount of the electron beam is an amount necessary and sufficient for the electron beam crosslinking of the oligomer component (that is, derived from the thermoplastic resin) generated by cutting the molecular chain of the thermoplastic resin in the melt extrusion molding step. For example, 10 to 500 kGy. If the irradiation amount is less than 10 kGy, the amount is insufficient for electron beam crosslinking of the oligomer component, and if the irradiation amount exceeds 500 kGy, the molecular chain of the thermoplastic resin is broken, which is not suitable.

  Thereby, the oligomer component of the belt surface layer can be recombined (immobilized) without deteriorating the physical properties as the intermediate transfer belt member (for example, crack resistance at the belt end portion by repeated use).

Next, the image forming apparatus according to the present invention will be described.
The image forming apparatus according to the present invention includes at least an electrostatic latent image on an image carrier (photosensitive drum 10, black photoconductor 10K, yellow photoconductor 10Y, magenta photoconductor 10M, cyan photoconductor 10C). An electrostatic latent image forming means (charging roller 20, exposure device, charging roller 20, exposure device 21) for forming a toner image, and an electrostatic latent image formed on the image carrier is converted into a toner image using toner. Developing means (black developing unit 45K, yellow developing unit 45Y, magenta developing unit 45M, cyan developing unit 45C, developing unit 61) and an intermediate transfer member (intermediate transfer member) 50) primary transfer means (roller 51, transfer roller 62) for transferring onto the recording medium, and secondary transfer means (transfer roller 80, secondary transfer device 22) for transferring the toner image on the intermediate transfer member onto the recording medium. When, An image forming apparatus including a fixing unit (fixing device 25) for fixing a toner image on a recording medium, wherein the intermediate transfer member is the intermediate transfer belt member (intermediate transfer belt member 1) of the present invention described above. It is characterized by being.

The specific configuration will be described below.
In the following embodiment, the image carrier referred to in the present invention refers to the photosensitive drum 10 or the black photosensitive member 10K, the yellow photosensitive member 10Y, the magenta photosensitive member 10M, and the cyan photosensitive member 10C. That means.
Further, the electrostatic latent image forming means in the present invention refers to the charging roller 20 and the exposure device, or the charging roller 20 and the exposure device 21.
The developing means in the present invention means the black developing unit 45K, the yellow developing unit 45Y, the magenta developing unit 45M, the cyan developing unit 45C, or the developing unit 61.
Further, the intermediate transfer member referred to in the present invention refers to the intermediate transfer member 50.
Further, the primary transfer means in the present invention refers to the roller 51 or the transfer roller 62.
The secondary transfer means referred to in the present invention refers to the transfer roller 80 or the secondary transfer device 22.
The fixing means in the present invention refers to the fixing device 25.

FIG. 3 shows a configuration example (1) of an image forming apparatus which is an embodiment of the electrophotographic forming apparatus of the present invention.
The image forming apparatus 100A includes a photosensitive drum 10, a charging roller 20 as a charging unit, an exposure device (not shown) as an exposure unit, and a developing unit (a black developing unit 45K and a yellow developing unit) as a developing unit. 45Y, magenta developing device 45M, cyan developing device 45C), intermediate transfer member 50, cleaning device 60 having a cleaning blade as a cleaning means, and static elimination lamp 70 as a static elimination means.

The intermediate transfer member 50 is an application of the intermediate transfer belt member 1 of the present invention. The intermediate transfer member 50 is stretched over three rollers 51 arranged on the inner side thereof, and can move in the direction of the arrow. A part of the three rollers 51 also functions as a transfer bias roller that can apply a predetermined transfer bias (primary transfer bias) to the intermediate transfer member 50.
Further, a cleaning device 90 having a cleaning blade is disposed in the vicinity of the intermediate transfer member 50. Further, a transfer roller 80 serving as a transfer unit capable of applying a transfer bias for transferring (secondary transfer) the toner image to the recording medium 95 is disposed to face the intermediate transfer member 50.
Further, around the intermediate transfer member 50, a corona charger 52 for applying a charge to the toner image on the intermediate transfer member 50, a contact portion between the photosensitive drum 10 and the intermediate transfer member 50, and the intermediate transfer member 50 are provided. And the contact portion of the recording medium 95.

  Black (K), yellow (Y), magenta (M), and cyan (C) developer units (black developer unit 45K, yellow developer unit 45Y, magenta developer unit 45M, cyan developer unit 45C) , A developer container (42K, 42Y, 42M, 42C), a developer supply roller (43K, 43Y, 43M, 43C), and a developing roller (44K, 44Y, 44M, 44C).

  In the image forming apparatus 100A, after the photosensitive drum 10 is uniformly charged by the charging roller 20, the exposure light 30 is exposed imagewise on the photosensitive drum 10 by an exposure device (not shown) to form an electrostatic latent image. Form. Next, a developer is supplied to the electrostatic latent image formed on the photosensitive drum 10 from a developing device (black developing device 45K, yellow developing device 45Y, magenta developing device 45M, cyan developing device 45C). Then, after developing to form a toner image, the toner image is transferred (primary transfer) onto the intermediate transfer member 50 by the transfer bias applied from the roller 51. Further, the toner image on the intermediate transfer member 50 is given a charge by the corona charger 52 and then transferred (secondary transfer) onto the recording medium 95. The toner remaining on the photosensitive drum 10 is removed by the cleaning device 60, and the photosensitive drum 10 is once discharged by the discharging lamp 70.

  As described above, in the image forming apparatus 100A, the intermediate transfer belt member of the present invention is used. Therefore, the belt characteristics of the intermediate transfer body 50 are not deteriorated even when an image is output for a long period of time. In addition, a high-quality image output can be obtained without the toner being fused.

FIG. 4 shows a configuration example (2) of the image forming apparatus which is an aspect of the electrophotographic forming apparatus of the present invention.
The image forming apparatus 100B is a tandem color image forming apparatus, and includes a copying apparatus main body 150, a paper feed table 200, a scanner 300, and an automatic document feeder (ADF) 400.
The copying machine main body 150 is provided with an intermediate transfer member 50 to which the intermediate transfer belt member 1 of the present invention is applied at the center. The intermediate transfer member 50 is stretched over the support rollers 14, 15 and 16, and can rotate in the direction of the arrow.

  A cleaning device 17 for removing the toner remaining on the intermediate transfer member 50 is disposed in the vicinity of the support roller 15. Further, four image forming units 18 of yellow, cyan, magenta, and black are arranged opposite to each other on the intermediate transfer member 50 stretched between the support roller 14 and the support roller 15 along the conveyance direction. A tandem developing device 120 is disposed.

  As shown in FIG. 5, the image forming means 18 for each color includes a photosensitive drum 10, a charging roller 20 that uniformly charges the photosensitive drum 10, and a black electrostatic latent image formed on the photosensitive drum 10. (K), yellow (Y), magenta (M), and cyan (C) are developed with each color developer to form a toner image, and each color toner image is transferred onto the intermediate transfer member 50. A transfer roller 62, a cleaning device 63, and a charge removal lamp 64.

  In addition, an exposure device 21 is disposed in the vicinity of the tandem developing device 120 (FIG. 4). The exposure device 21 exposes the exposure light L on the photoconductor drum 10 (black photoconductor 10K, yellow photoconductor 10Y, magenta photoconductor 10M, cyan photoconductor 10C) to form an electrostatic latent image. .

  Further, a secondary transfer device 22 is disposed on the side of the intermediate transfer member 50 opposite to the side on which the tandem developing device 120 is disposed. The secondary transfer device 22 includes a secondary transfer belt 24, which is an endless belt stretched between a pair of rollers 23, and a recording medium conveyed on the secondary transfer belt 24 and the intermediate transfer member 50 can contact each other. It has become.

  A fixing device 25 is disposed in the vicinity of the secondary transfer device 22. The fixing device 25 includes a fixing belt 26 that is an endless belt, and a pressure roller 27 that is arranged to be pressed against the fixing belt 26.

  Further, in the vicinity of the secondary transfer device 22 and the fixing device 25, a reversing device 28 for reversing the recording medium in order to form an image on both sides of the recording medium is disposed.

  Next, full color image formation (color copy) in the image forming apparatus 100B will be described. First, a document is set on the document table 130 of the automatic document feeder (ADF) 400, or the automatic document feeder 400 is opened and a document is set on the contact glass 32 of the scanner 300. close up. Next, when a start switch (not shown) is pressed, when the document is set on the automatic document feeder 400, the document is transported and moved onto the contact glass 32, and then the document is placed on the contact glass 32. When set, the scanner 300 is immediately driven, and the first traveling body 33 and the second traveling body 34 travel. At this time, light from the light source is emitted from the first traveling body 33, and reflected light from the document surface is reflected by a mirror in the second traveling body 34 and received by the reading sensor 36 through the imaging lens 35. . Thus, a color original (color image) is read, and image information of each color of black, yellow, magenta, and cyan is obtained.

  Further, after an electrostatic latent image of each color is formed on the photosensitive drum 10 based on the obtained image information of each color by the exposure device 21, the electrostatic latent image of each color is supplied from the developing device 61 of each color. The developed developer is used to form a toner image of each color. The formed toner images of the respective colors are sequentially transferred (primary transfer) on the intermediate transfer member 50 that is rotated and moved by the support rollers 14, 15, and 16, thereby forming a composite toner image on the intermediate transfer member 50. .

  In the paper feed table 200, one of the paper feed rollers 142 is selectively rotated, the recording medium is fed out from one of the paper feed cassettes 144 provided in multiple stages in the paper bank 143, and separated one by one by the separation roller 145. Then, the sheet is fed to the sheet feeding path 146, conveyed by the conveying roller 147, guided to the sheet feeding path 148 in the copying machine main body 150, and abutted against the registration roller 49 which is a positioning roller and stopped. Alternatively, the recording medium on the manual feed tray 151 is fed out, separated one by one by the separation roller 58, put into the manual feed path 53, and abutted against the registration roller 49 and stopped. The registration roller 49 is generally used while being grounded, but may be used with a bias applied in order to remove paper dust from the recording medium.

Then, the registration roller 49 is rotated in synchronization with the composite toner image formed on the intermediate transfer member 50, and the recording medium is sent between the intermediate transfer member 50 and the secondary transfer device 22, so that the composite toner image is recorded on the recording medium. Transfer on top (secondary transfer).
The recording medium onto which the composite toner image has been transferred is conveyed by the secondary transfer device 22 and sent out to the fixing device 25. In the fixing device 25, the composite toner image is fixed on the recording medium by being heated and pressed by the fixing belt 26 and the pressure roller 27. Thereafter, the recording medium is switched by the switching claw 55 and discharged by the discharge roller 56, and is stacked on the discharge tray 57. Alternatively, it is switched by the switching claw 55, reversed by the reversing device 28, guided again to the transfer position, forms an image on the back surface, then ejected by the ejection roller 56, and stacked on the paper ejection tray 57.
The toner remaining on the intermediate transfer member 50 after the composite toner image is transferred is removed by the cleaning device 17.

  As described above, in the image forming apparatus 100B, the intermediate transfer belt member of the present invention is used. Therefore, the belt characteristics of the intermediate transfer member 50 are not deteriorated even when an image is output for a long period of time. In addition, a high-quality image output can be obtained without the toner being fused.

  Hereinafter, the present invention will be described in more detail with reference to test examples. However, the following description is intended to facilitate understanding of the present invention and is not intended to limit the present invention.

[Test Example 1]
Under the following conditions, melt extrusion was performed, and the presence or absence of oligomer components on the outer peripheral surface was examined. For the thermosetting resin, polyimide (PI, a polyimide belt used in a commercially available printer) was selected.

(1) Resin composition A thermoplastic resin (100 parts by weight) and a conductive agent (8 parts by weight) are kneaded for 80 minutes while heating at a temperature not higher than the melting point of the resin with a kneader, and further for 30 minutes using two rolls. The conductive agent was dispersed and pelletized with a pelletizer to obtain a pellet-shaped resin composition. The following thermoplastic resins and conductive agents were used.
-Thermoplastic resin: Select one from the following four types.
・ Polybutylene terephthalate (PBT, trade name Nova Duran 5505S, manufactured by Mitsubishi Engineering Plastics)
・ Polycarbonate (PC, trade name Iupilon S3000, manufactured by Mitsubishi Engineering Plastics) and polyester elastomer (TPEE, trade name Perprene S3001N, manufactured by Toyobo) (PC / Pes)
・ Polyvinylidene fluoride (PVDF, trade name KAYNER720, manufactured by Arkema)
-Conductive agent: Carbon black (CB, Denka black granular product average primary particle size 35 nm, manufactured by Denki Kagaku)

(2) Extrusion molding A pellet-shaped resin composition was extruded into a cylindrical shape with an annular die to produce a molded belt having a thickness of 100 μm.

(3) GPC analysis 1 g of a belt piece obtained by shaving the outer peripheral surface of the obtained molded belt was immersed in 20 g of tetrahydrofuran (THF) for 1 hour, and the eluted component was analyzed by gel permeation chromatography (GPC, manufactured by Shimadzu Corporation). Analysis was conducted to measure the weight average molecular weight in terms of PS, and the presence or absence of the oligomer component was investigated.

The results of GPC analysis are shown in FIG.
As shown in FIG. 6, formation of oligomer components was observed with polybutylene terephthalate (PBT), a mixed resin of polycarbonate and polyester elastomer (PC / Pes), and polyvinylidene fluoride (PVDF). This is because the resin molecular chains were cut by heat and shearing force in the vicinity of being extruded from the die of the extruder, and a large amount of oligomer components were formed on the surface layer of the molded belt, and the surface layer was air immediately after being extruded from the die. It can be considered that the oligomer component is also generated by oxidative decomposition by contact with oxygen in the inside.

[Test Example 2]
The intermediate transfer belt member of the present invention was produced and evaluated under the following conditions.
Example 1
(1) Resin composition As a thermoplastic resin, polybutylene terephthalate (PBT, trade name Novaduran 5505S, manufactured by Mitsubishi Engineering Plastics) 100 parts by weight of conductive carbon black (Denka black granular product average primary particle size 35 nm), (Electric Chemical) 8 parts by weight, kneaded with a kneader at 150 ° C. for 80 minutes, further dispersed with a two-roller for 30 minutes and pelletized with a pelletizer. I got a thing.
(2) Extrusion Molding Next, a pellet-shaped resin composition was used to extrude into a cylindrical shape with an annular die to produce a molded belt having a thickness of 100 μm.
The electrical characteristics of the molded belt were measured for the resistivity of the molded belt using Hiresta UP MCP-HT450 type (manufactured by Dia Instruments Co., Ltd.). The resistivity was measured after applying 250 V for 10 seconds, and the average of a plurality of measurement points was taken as the measured value. A URS probe was used as a measurement probe. The volume resistivity ρv of the belt formed in Example 1 was Log (ρv (: 250V)) = 9.3.
(3) Electron beam irradiation Next, in an electron irradiation device (manufactured by Hamamatsu Photonics), a metal cylinder is inserted into the inner diameter part of the forming belt, and while rotating this cylinder, both sides in the axial direction of the metal cylinder An intermediate transfer belt member was obtained by irradiating with an electron beam from an irradiation device arranged in the above. The irradiation conditions at this time were an acceleration voltage of 30 kV and an irradiation dose of 100 kGy.

(Example 2)
In Example 1, an intermediate transfer belt member was produced under the same conditions as in Example 1 except that the electron beam irradiation amount was 200 kGy.

(Example 3)
In Example 1, an intermediate transfer belt member was produced under the same conditions as in Example 1 except that the electron beam irradiation amount was 500 kGy.

Example 4
In Example 1, an intermediate transfer belt member was produced under the same conditions as in Example 1 except that the electron beam acceleration voltage was 50 kV.

(Example 5)
In Example 1, an intermediate transfer belt member was produced under the same conditions as in Example 1 except that the electron beam acceleration voltage was 50 kV and the irradiation amount was 500 kGy.

(Example 6)
In Example 1, before kneading with a kneader, polybutylene terephthalate (PBT), conductive carbon black (CB) and 0.5 parts by weight of triallyl isocyanurate (TAIC: manufactured by Nippon Kayaku Co., Ltd.) as a crosslinking agent are added. Otherwise, an intermediate transfer belt member was produced under the same conditions as in Example 1.
The electrical characteristics of the molded belt were measured for the resistivity of the molded belt using Hiresta UP MCP-HT450 type (manufactured by Dia Instruments Co., Ltd.). The resistivity was measured after applying 250 V for 10 seconds, and the average of a plurality of measurement points was taken as the measured value. A URS probe was used as a measurement probe. The volume resistivity ρv of the belt molded in Example 1 was Log (ρv (: 250V)) = 8.5.

(Example 7)
In Example 6, an intermediate transfer belt member was produced under the same conditions as in Example 6 except that the electron beam acceleration voltage was 50 kV.

(Example 8)
(1) Resin composition As thermoplastic resin, polycarbonate (PC, trade name Iupilon S3000, manufactured by Mitsubishi Engineering Plastics) 80 parts by weight, polyester elastomer (TPEE, Perprene S3001N, manufactured by Toyobo), as a crosslinking agent 0.5 parts by weight of triallyl isocyanurate (TAIC: manufactured by Nippon Kayaku Co., Ltd.) and 8 parts by weight of conductive carbon black (Denka Black granular product average primary particle size: 35 nm, manufactured by Denki Kagaku) as a conductive agent After kneading at 150 ° C. for 80 minutes, the conductive agent was further dispersed for 30 minutes using two rolls and pelletized with a pelletizer to obtain a pellet-shaped resin composition.
(2) Extrusion Molding Next, a pellet-shaped resin composition was used to extrude into a cylindrical shape with an annular die to produce a molded belt having a thickness of 100 μm.
The electrical characteristics of the molded belt were measured for the resistivity of the molded belt using Hiresta UP MCP-HT450 type (manufactured by Dia Instruments Co., Ltd.). The resistivity was measured after applying 250 V for 10 seconds, and the average of a plurality of measurement points was taken as the measured value. A URS probe was used as a measurement probe. The volume resistivity ρv of the belt molded in Example 1 was Log (ρv (: 250V)) = 9.0.
(3) Electron beam irradiation Next, in an electron irradiation device (manufactured by Hamamatsu Photonics), a metal cylinder is inserted into the inner diameter part of the forming belt, and while rotating this cylinder, both sides in the axial direction of the metal cylinder An intermediate transfer belt member was obtained by irradiating with an electron beam from an irradiation device arranged in the above. The irradiation conditions at this time were an acceleration voltage of 70 kV and an irradiation amount of 200 kGy.

Example 9
In Example 8, an intermediate transfer belt member was produced under the same conditions as in Example 8 except that the electron beam irradiation amount was 500 kGy.

(Example 10)
(1) Resin composition As thermoplastic resin, 100 parts by weight of polyvinylidene fluoride (PVDF, trade name KAYNER720, manufactured by Arkema), conductive carbon black (Denka black granular product average primary particle size 35 nm, manufactured by Denki Kagaku) as a conductive agent ) 8 parts by weight, 1 part by weight of an ionic conductive agent (ion, tetrabutylammonium hydrogen sulfate, Koei Chemical Co., Ltd.) and 0.5 weight of triallyl isocyanurate (TAIC: Nippon Kayaku) as a cross-linking agent Partly added, kneaded at 150 ° C. for 80 minutes with a kneader, further dispersed with a two rolls for 60 minutes, and pelletized with a pelletizer to obtain a pellet-shaped resin composition.
(2) Extrusion Molding Next, a pellet-shaped resin composition was used to extrude into a cylindrical shape with an annular die to produce a molded belt having a thickness of 100 μm.
The electrical characteristics of the molded belt were measured for the resistivity of the molded belt using Hiresta UP MCP-HT450 type (manufactured by Dia Instruments Co., Ltd.). The resistivity was measured after applying 250 V for 10 seconds, and the average of a plurality of measurement points was taken as the measured value. A URS probe was used as a measurement probe. The volume resistivity ρv of the belt molded in Example 1 was Log (ρv (: 250V)) = 10.7.
(3) Electron beam irradiation Next, in an electron irradiation device (manufactured by Hamamatsu Photonics), a metal cylinder is inserted into the inner diameter part of the forming belt, and while rotating this cylinder, both sides in the axial direction of the metal cylinder An intermediate transfer belt member was obtained by irradiating with an electron beam from an irradiation device arranged in the above. The irradiation conditions at this time were an acceleration voltage of 30 kV and an irradiation dose of 100 kGy.

(Example 11)
In Example 8, an intermediate transfer belt member was manufactured under the same conditions as in Example 8 except that the electron beam acceleration voltage was 50 kV.

(Comparative Example 1)
In Example 1, an electron beam irradiation process was not performed, and an intermediate transfer belt member was manufactured under the same conditions as in Example 1 except for that.

(Comparative Example 2)
In Example 1, an intermediate transfer belt member was produced under the same conditions as in Example 1 except that the electron beam acceleration voltage was 100 kV.

(Comparative Example 3)
In Example 1, an intermediate transfer belt member was produced under the same conditions as in Example 1 except that the electron beam acceleration voltage was 150 kV.

(Comparative Example 4)
In Example 10, an intermediate transfer belt member was produced under the same conditions as in Example 8 except that the electron beam acceleration voltage was 150 kV.

(Evaluation item)
The intermediate transfer belt member obtained as described above was mounted as an intermediate transfer body on a commercially available printer (IPSiO SP C220: manufactured by Ricoh Co., Ltd.), and the following evaluation was performed.
(1) Image quality (toner transferability)
Using a commercially available printer, output fine line images at intervals of about 200 μm on plain paper (T6200: manufactured by Ricoh Co., Ltd.), visually observe the image evaluation of the fine lines with an optical microscope, and scatter the toner into fine lines. The evaluation was made with ○ when there was no toner, △ when the scattering of the toner was observed but there was no disturbance in the state of the fine line, and × when the scattering of the toner was observed and the disturbance of the thin line was observed .
(2) Contamination resistance of the belt (attachment of toner to the belt surface)
A commercially available printer was used to print 10,000 sheets of plain paper (T6200: manufactured by Ricoh Co., Ltd.), and the surface of the intermediate transfer belt member was visually observed. At this time, the evaluation was made by assuming that no toner adhesion was observed on the belt surface, ◯ a slight toner adhesion being recognized, and a state where toner adhesion was clearly recognized on the belt surface.
(3) Cracking of belt With a commercially available printer, 10,000 sheets were printed on plain paper (T6200: manufactured by Ricoh Co., Ltd.), and the end of the intermediate transfer belt member was visually observed. At this time, the case where no cracks or cracks were observed at the belt end was evaluated as ◯, and the case where cracks or cracks were observed at the belt end was evaluated as x.
The above evaluation results are shown in Table 1.

  Although the present invention has been described with the embodiments shown in the drawings, the present invention is not limited to the embodiments shown in the drawings, and other embodiments, additions, modifications, deletions, etc. Can be changed within the range that can be conceived, and any embodiment is included in the scope of the present invention as long as the effects and advantages of the present invention are exhibited.

DESCRIPTION OF SYMBOLS 1 Intermediate transfer belt member 10 Photoconductor drum 10K Photoconductor for black 10Y Photoconductor for yellow 10M Photoconductor for magenta 10C Photoconductor for cyan 14, 15, 16 Support roller 17 Cleaning device 18 Image forming means 20 Charging roller 21 Exposure device 22 Secondary transfer device 23 Roller 24 Secondary transfer belt 25 Fixing device 26 Fixing belt 27 Pressure roller 28 Reversing device 30 Exposure light 32 Contact glass 33 First traveling body 34 Second traveling body 35 Imaging lens 36 Reading sensor 42K, 42Y , 42M, 42C Developer container 43K, 43Y, 43M, 43C Developer supply roller 44K, 44Y, 44M, 44C Developer roller 45K Black developer 45Y Yellow developer 45M Magenta developer 45C Cyan developer 49 Registro La 50 Intermediate transfer member 51 Roller 52 Corona charger 53 Manual paper feed path 55 Switching claw 56 Discharge roller 57 Discharge tray 58 Separation roller 60 Cleaning device 61 Developer 62 Transfer roller 63 Cleaning device 64 Discharge lamp 70 Discharge lamp 80 Transfer roller DESCRIPTION OF SYMBOLS 90 Cleaning apparatus 95 Recording medium 100A, 100B Image forming apparatus 120 Tandem type developing device 130 Document stand 142 Paper feed roller 143 Paper bank 144 Paper feed cassette 145 Separation roller 146 Paper feed path 147 Conveyance roller 148 Paper feed path 150 Copier main body 151 Bypass tray 200 Paper feed table 300 Scanner 400 Automatic document feeder L Exposure light

JP 2002-202668 A

Claims (10)

  A resin composition containing at least a thermoplastic resin and a conductive agent is melt-extruded into an endless belt shape, and then the outer surface of the belt is irradiated with an electron beam with an acceleration voltage of 10 to 70 kV to derive from the thermoplastic resin on the belt surface layer An intermediate transfer belt member obtained by electron beam crosslinking of the oligomer component. When the resin composition is melt-extruded into the endless belt shape, the belt molded product has a tensile elastic modulus of 1500 Mpa or more and less than 4000 Mpa, and a volume resistivity of 1.0 × 10 ⁶ Ω · cm or more, 1 The intermediate transfer belt member according to claim 1, wherein the intermediate transfer belt member is less than 0.0 × 10 ¹² Ω · cm.   The intermediate transfer belt member according to claim 1, wherein the thermoplastic resin includes any one of a polyester resin, a polycarbonate resin, a polyvinylidene fluoride resin, and a polyphenyl sulfide resin.   The intermediate transfer belt member according to claim 3, wherein the thermoplastic resin includes a polyester-based resin.   The intermediate transfer belt member according to claim 1, wherein the resin composition includes a crosslinking agent.   The cross-linking agent is any one of triallyl isocyanurate, triallyl cyanurate, trimethallyl isocyanurate, diallyl monoglycidyl isocyanurate, or a mixture of any two or more thereof. The intermediate transfer belt member according to 5.   The intermediate transfer belt member according to claim 1, wherein the conductive agent is conductive fine particles having an average primary particle diameter of 5 to 50 nm.   The intermediate transfer belt member according to claim 1, wherein the intermediate transfer belt member has a thickness of 50 to 200 μm. A melt extrusion molding step of forming a resin composition containing at least a thermoplastic resin and a conductive agent into an endless belt shape;
An electron beam irradiation step of irradiating the belt outer peripheral surface with an electron beam having an acceleration voltage of 10 to 70 kV to crosslink the oligomer component derived from the thermoplastic resin on the belt surface layer;
A process for producing an intermediate transfer belt member, comprising: At least an electrostatic latent image forming means for forming an electrostatic latent image on the image carrier, and a developing means for converting the electrostatic latent image formed on the image carrier into a toner image using toner; A primary transfer means for transferring a toner image on the image carrier onto an intermediate transfer body; a secondary transfer means for transferring the toner image on the intermediate transfer body onto a recording medium; and a toner on the recording medium. An image forming apparatus comprising: a fixing unit that fixes an image;
An image forming apparatus, wherein the intermediate transfer member is the intermediate transfer belt member according to claim 1.