JP2007179013A - Endless belt for image forming apparatus and image forming apparatus with same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an endless belt for an image forming apparatus having a high color shift detecting performance over a long period of time from the initial stage and an image forming apparatus having the endless belt for an image forming apparatus. <P>SOLUTION: In the endless belt for an image forming apparatus having at least two layers of an inner layer and an outermost layer, the average regular reflectance of the surface of the outermost layer is ≥5.0% or more and the fluctuation of the regular reflectance of the surface of the outermost layer is kept within ±10%. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an endless belt for an image forming apparatus and an image forming apparatus having the same. Specifically, the present invention relates to an endless belt such as an intermediate transfer belt or a transfer material conveying belt used in an image forming apparatus such as a copying machine, a laser beam printer, or a facsimile, and an image forming apparatus having the same.

  First, a case where an endless belt for an image forming apparatus is used as a transfer material conveyance belt will be described.

FIG. 1 is a diagram showing a schematic configuration of an image forming apparatus (color image forming apparatus) having a transfer material conveying belt.
The color image forming apparatus having the configuration shown in FIG. 1 includes four drum-shaped photosensitive members (photosensitive drums) as image carriers (photosensitive drums 1a, 1b, 1c, and 1d).

Further, around the photosensitive drums 1a, 1b, 1c, and 1d, respectively, in order according to the rotation direction of the photosensitive drum (counterclockwise in the figure),
Charging means for uniformly charging the surface of the photosensitive drum (chargers 2a, 2b, 2c, 2d),
Exposure means (laser scanners 3a, 3b, 3c, 3d) for irradiating a laser beam based on image information to form an electrostatic latent image on the surface of the photosensitive drum;
Developing means (developing devices 4a, 4b, 4c, 4d) for attaching toner to the electrostatic latent image and developing it as a toner image;
Transfer means (transfer rollers 5a, 5b, 5c, 5d) for transferring the toner image to a transfer material (paper, OHP film, etc.) S;
Cleaning means (cleaners 6a, 6b, 6c, 6d) for removing residual transfer toner remaining on the surface of the photosensitive drum after transfer
Are arranged to constitute an image forming unit for each color.

  The photosensitive drums 1a, 1b, 1c, 1d, the chargers 2a, 2b, 2c, 2d, the developing devices 4a, 4b, 4c, 4d, and the cleaners 6a, 6b, 6c, 6d are as shown in FIG. Each is integrally formed into a cartridge to constitute a process cartridge (process cartridges 7a, 7b, 7c, 7d).

  The transfer material S is sequentially conveyed to the image forming unit for each color by the transfer material conveyance belt 9, and the toner images for each color are sequentially superimposed and transferred to form a composite toner image, which is then synthesized by a fixing unit (fixing device 10). The toner image is fixed and discharged out of the apparatus.

  Next, a case where an endless belt for an image forming apparatus is used as an intermediate transfer belt will be described.

FIG. 2 is a diagram showing a schematic configuration of an image forming apparatus (color image forming apparatus) having an intermediate transfer belt.
The color image forming apparatus having the configuration shown in FIG. 2 also includes four drum-shaped photosensitive members (photosensitive drums) as image carriers (photosensitive drums 1a, 1b, 1c, and 1d).

Further, around the photosensitive drums 1a, 1b, 1c, and 1d, respectively, in order according to the rotation direction of the photosensitive drum (counterclockwise in the figure),
Charging means for uniformly charging the surface of the photosensitive drum (chargers 2a, 2b, 2c, 2d),
Exposure means (laser scanners 3a, 3b, 3c, 3d) for irradiating a laser beam based on image information to form an electrostatic latent image on the surface of the photosensitive drum;
Developing means (developing devices 4a, 4b, 4c, 4d) for attaching toner to the electrostatic latent image and developing it as a toner image;
Primary transfer means (primary transfer rollers 5pa, 5pb, 5pc, 5pd) for primary transfer of the toner image to the intermediate transfer belt 11, and
Cleaning means (cleaners 6a, 6b, 6c, 6d) for removing residual toner remaining on the surface of the photosensitive drum after primary transfer
Are arranged to constitute an image forming unit for each color.

  The photosensitive drums 1a, 1b, 1c, 1d, the chargers 2a, 2b, 2c, 2d, the developing devices 4a, 4b, 4c, 4d, and the cleaners 6a, 6b, 6c, 6d are as shown in FIG. Each is integrally formed into a cartridge to constitute a process cartridge (process cartridges 7a, 7b, 7c, 7d).

  On the intermediate transfer belt 11, the toner images of the respective colors are sequentially superimposed and transferred in the image forming portions of the respective colors, thereby forming a composite toner image.

  The transfer material S is conveyed between the intermediate transfer belt 11 and the secondary transfer unit (secondary transfer roller 5s), and after the composite toner image is transferred, the composite toner image is fixed by the fixing unit (fixing device 10). Is discharged from the apparatus.

  As described above, the color image forming apparatus superimposes a total of four color images of the first to fourth colors (generally yellow, magenta, cyan and black) on the transfer material or the intermediate transfer belt. A color image (full color image) is formed. Therefore, if the writing positions of the four colors in the sub-scanning direction (moving direction of the transfer material or intermediate transfer belt) do not match, a problem on the image called so-called color misregistration occurs. Other causes of color misregistration include misregistration of the writing position in the main scanning direction (direction perpendicular to the moving direction of the transfer material or intermediate transfer belt) and color misregistration due to variations in main scanning line width. .

  In order to correct color misregistration in the sub-scanning direction and main scanning direction, a pattern for detecting color misregistration is formed for each color on the transfer material conveyance belt or intermediate transfer belt, and the transfer material conveyance belt downstream portion or intermediate transfer belt downstream Detected by a pair of optical sensors provided on both sides of the image forming section, and according to the detected amount of deviation, adjusts the exposure timing of the image forming section and adjusts the speed of a plurality of photosensitive drums, transfer material conveying belts or intermediate transfer belts It is known to perform various adjustments such as

FIG. 3 is a diagram for explaining the color misregistration detection means. As an example, the case of a transfer material conveying belt is given, but the same applies to the case of an intermediate transfer belt.
In FIG. 3, reference numeral 20 denotes a color misregistration detecting means, which is composed of a light emitting element and a light receiving element. A light emitting element 21 is an LED that emits light having a wavelength in the infrared region, for example. Reference numeral 22 denotes a light receiving element (for example, a photosensor). 9 is a transfer material conveyance belt, and 23 is a pattern for detecting color misregistration. Reference numeral 24 denotes a light emission optical path from the light emitting element 21, and reference numeral 25 denotes a light reception optical path received by the light receiving element 22 among the reflected light from the transfer material conveyance belt 9 or the color shift detection pattern 23. The light emitting unit and the light receiving unit are configured by a regular reflection optical system with the transfer material conveyance belt 9 as a reflection surface, and a difference in reflectance between the transfer material conveyance belt 9 and the color misregistration detection pattern 23 is reflected. The position of the color misregistration detection pattern is detected based on the difference in reflectance.

Therefore, the endless belt used in the image forming apparatus needs to have a high regular reflectance on the surface in order to increase the difference in regular reflectance with the toner, and the regular reflectance of the surface due to long-term use. In order to suppress the decrease, it is also necessary to have high rubbing resistance.
From such a viewpoint, conventionally, as an endless belt for an image forming apparatus, an endless belt made of polyimide, an endless belt having a multilayer structure using a hard coat material as an outermost layer, and the like have been proposed. (For example, see Patent Document 1 and Patent Document 2.)
Japanese Patent Laid-Open No. 11-161036 Japanese Patent Laid-Open No. 11-024428

  However, when polyimide is used for the endless belt, the reaction process is long, and the cost tends to increase. Further, the surface hardness is as low as about 2H pencil hardness. For this reason, when used for a long period of time, the surface is scraped and irregularities are generated by the photoconductor, roller, transfer material, etc., and the regular reflectance of the surface of the endless belt decreases. When the regular reflectance on the surface of the endless belt is lowered, the difference from the regular reflectance of the toner is reduced, so that sufficient color misregistration detection performance cannot be obtained.

  In addition, some conventional endless belts having a hard coat material as the outermost layer employ a fluororesin as the outermost layer in order to improve toner releasability. However, since fluororesin is a low refractive index material, when color misregistration detection is performed using regular reflection on the surface of the endless belt, the difference in regular reflectance between the surface of the toner and the endless belt becomes small. For this reason, error factors such as noise increase, and it is difficult to exhibit stable color misregistration detection performance.

  Further, when a conventional multi-layered endless belt is used, the color misregistration detection performance may be particularly deteriorated. This is because the incident light of the color misregistration detection sensor is transmitted through the outermost layer of the multi-layered endless belt, reflected at the interface between the outermost layer and the inner layer, and from the outer surface reflected light of the outermost layer and the interface between the outermost layer and the inner layer surface. This is because the reflected light of the light interferes. In particular, when the thickness of the outermost layer varies in the vicinity of 1/4 integral multiple of the wavelength of incident light of the color shift detection sensor, the incident light incident on the photo sensor of the color shift detection sensor varies greatly. As a result, the color misregistration detection performance is degraded.

  An object of the present invention is to provide an endless belt for an image forming apparatus having high color misregistration detection performance from the initial stage to a long-term use, and an image forming apparatus having the endless belt for an image forming apparatus.

According to the present invention, in an endless belt for an image forming apparatus having at least two layers of an inner layer and an outermost layer, the average regular reflectance of the surface of the outermost layer is 5.0% or more, and the regular reflectance of the surface of the outermost layer is Is an endless belt for an image forming apparatus, characterized in that the variation is within ± 10% of the average regular reflectance.
The present invention is also an image forming apparatus having the endless belt for the image forming apparatus.

  According to the present invention, it is possible to provide an endless belt for an image forming apparatus having high color misregistration detection performance from the beginning to a long-term use, and an image forming apparatus having the endless belt for an image forming apparatus.

  The regular reflectance of the color misregistration detection pattern made of toners such as magenta, yellow, cyan and black is about 2.5% or less. Therefore, when using the difference in regular reflectance between the toner and the surface of the endless belt when detecting color misregistration, in order to increase the difference in regular reflectance, the surface of the endless belt, that is, the outermost layer of the endless belt. It is necessary that the average regular reflectance of the surface is 5.0% or more. If the average regular reflectance of the outermost layer surface of the endless belt is less than 5.0%, it is difficult to recognize the position of the color misregistration detection pattern by the color misregistration detection sensor with sufficient accuracy, and the color misregistration detection performance decreases. To do.

  Further, the variation in regular reflectance on the surface of the outermost layer of the endless belt needs to be within ± 10% of the average regular reflectance. When the variation in regular reflectance is larger than ± 10% of the average regular reflectance, the regular reflected light from the surface of the endless belt is input to the sensor with a variation larger than ± 10%. It can lead to errors. If there is a false detection, the color misregistration detection pattern cannot be detected stably.

Here, “average regular reflectance” and “variation in regular reflectance” are measured and defined as follows.
That is, a spectrophotometer (trade name: U4000) manufactured by Hitachi, Ltd. was used as the measuring device, and a measurement sample obtained by cutting an endless belt to be measured into a 20 mm square was used. And the incident angle of the light to a measurement sample was 15 degrees, and the average value of the regular reflectance in the wavelength range of 830-870 nm was made into the regular reflectance in the measurement location. Then, this measurement was performed at 30 points in the endless belt, and a value obtained by averaging the regular reflectances at the respective measurement points was defined as the average regular reflectance of the endless belt.
Further, when the value of the average regular reflectance is x and the value farthest from the average regular reflectance among the regular reflectances of the respective measurement points is y, {(y−x) / x} × 100 [ %] Is the variation in regular reflectance of the endless belt.

When the endless belt has a multi-layer configuration (a configuration of two or more layers), it is possible to functionally separate the characteristics required for an endless belt for an image forming apparatus into each layer.
For the outermost layer of the endless belt, it is preferable to employ a high-hardness material such as a curable resin as a binding material from the viewpoint of imparting a function of surface characteristics, particularly a function of wear resistance. For the inner layer of the endless belt, from the viewpoint of imparting strength that can be used as an endless belt, it is preferable to employ an inexpensive thermoplastic resin or rubber having mechanical durability. Furthermore, the inner layer is preferably a laminated type in which the inner side is a resin layer and the outer side (outermost layer side) is a rubber layer.

  The abrasion resistance of the endless belt is preferably such that the mass reduction rate after the Taber abrasion test (ASTM-D-1175, load 500 g, 500 revolutions) is 0.10% or less. From another viewpoint, the pencil hardness is preferably larger than 2H.

The outermost layer is preferably a hard coat layer using a hard coat material (organic material or inorganic material) capable of achieving wear resistance, high hardness, and high refractive index.
Examples of the organic material include melamine resin, urethane resin, alkyd resin, and acrylic resin. Examples of the inorganic material include alkoxylane, alkoxyzirconium, and silicate. Among these, acrylic resin is particularly preferable from the viewpoint of high hardness and applicability. The acrylic resin can be obtained by curing an acrylic monomer (for example, dipentaerythritol hexaacrylate), a prepolymer of acrylic resin, or the like.

  Moreover, it is preferable if the refractive index of the outermost layer is 1.60 or more because it becomes easy to achieve an average regular reflectance of 5.0% or more on the surface of the outermost layer. On the other hand, the refractive index of the outermost layer is preferably 1.80 or less from the viewpoint of easy confirmation of a partial decrease in average regular reflectance due to partial defects in the outermost layer, such as scratches.

  In order to obtain the outermost layer having a high refractive index, it is preferable to add fine particles having a high refractive index to the hard coat material. Examples of the fine particles having a high refractive index include tin oxide (refractive index 2.0), phosphorus-doped tin oxide (refractive index 2.0), indium tin oxide (refractive index 2.0), and antimony tin oxide (refractive index 2. 1), zinc aluminum oxide (refractive index 2.1), antimony pentoxide-zinc oxide (refractive index 2.0), titanium oxide (refractive index 2.4 to 2.7), cerium oxide (refractive index 2.3). ), Zinc oxide (refractive index 2.1), zirconium oxide (refractive index 2.1), antimony oxide (refractive index 2.1), indium oxide (refractive index 2.0), and the like. It is done. Among these, as the fine particles added to the outermost layer, titanium oxide that can increase the refractive index of the outermost layer with addition of a small amount, and antimony pentoxide-zinc oxide that can impart conductivity to the outermost layer. preferable. The amount of these fine particles added is preferably adjusted so that the outermost layer has a refractive index of 1.60 to 1.80.

  Further, from the viewpoint of suppressing diffuse reflection on the surface of the outermost layer, the particle diameter of the fine particles added to the outermost layer is preferably 30 nm or less, and more preferably 20 nm or less.

As the light emitting element 21 of the color misregistration detecting unit 20 used in the image forming apparatus, an element that emits light having a wavelength in the infrared region (830 to 870 nm) is often used. Therefore, in order to suppress reflection at the interface between the outermost layer and the inner layer, it is preferable to add an infrared absorber to the outermost layer. As the infrared absorber added to the outermost layer, various infrared absorbers can be appropriately selected and used. As an infrared absorber, for example,
Metal complex compounds such as nickel complex compounds, nitroso compounds and their metal complexes, cyanine compounds, squarylium compounds, thiol nickel complex compounds, naphthalocyanine compounds, triallylmethane compounds, imonium compounds, diimonium compounds , Naphtholine compounds, anthraquinone compounds, amino compounds, aminium salt compounds, metal sulfides and thiourea compounds, phthalocyanine compounds, fluorine-containing phthalocyanine compounds, copper compounds bisthiourea compounds, phosphorus compounds and copper compounds, phosphate esters Oxidation of organic compounds such as phosphate copper compounds obtained from the reaction of compounds with copper compounds, and metals belonging to periodic table 4A, 5A or 6A such as tantalum oxide, niobium oxide, zirconium oxide and titanium dioxide , And carbides or borides, zinc oxide, indium oxide, tin oxide, zinc sulfide, indium tin oxide, antimony tin oxide, cerium oxide, inorganic compounds such as carbon black. Among these, in the present invention, organic compounds such as nickel complexes, phosphorus compounds, antimony compounds, and phthalocyanine compounds are preferable. Specific examples include the YKR (trade name) series manufactured by Yamamoto Chemical Co., the Kayasorb (trade name) series manufactured by Nippon Kayaku Co., Ltd., and the Excolor (trade name) series manufactured by Nippon Shokubai Co., Ltd.

  The infrared transmittance of the outermost layer is preferably 40% or less. When the infrared transmittance of the outermost layer is larger than 40%, infrared rays are reflected at the interface between the outermost layer and the inner layer, and the reflected light at the surface of the outermost layer interferes with the reflected light at the interface between the outermost layer and the inner layer. It becomes easy to do.

The material constituting the inner layer is preferably a material having an elastic modulus of 1 GPa or more, and particularly preferably a thermoplastic resin that is easily available at a low cost. As a thermoplastic resin, for example,
Polyamide, polyacetal, polyarylate, polycarbonate, polyphenylene ether, polyethylene terephthalate, polysulfone, polyether sulfone, polyphenylene sulfide, polybutylene terephthalate, polyether ether ketone, polyvinylidene fluoride, ethylene tetrafluoroethylene copolymer, tetrafluoroethylene Perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, polyvinyl fluoride, acrylic resin, alkyl acrylate ester copolymer, polyether ester copolymer, polyether amide copolymer, polyurethane copolymer A polymer etc. are mentioned. Among these, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyvinylidene fluoride, and ethylenetetrafluoroethylene copolymer are particularly preferable. In the present invention, one of these thermoplastic resins or one made of a mixture thereof can be used.

In order to impart elasticity to the endless belt for an image forming apparatus, a layer made of an elastomer can be disposed as one of the inner layers. As an elastomer, for example,
Natural rubber, butadiene polymer, styrene-isoprene polymer, butadiene-styrene copolymer and hydrogenated products thereof (including random copolymer, block copolymer, graft copolymer, etc.), isoprene polymer, Chlorobutadiene polymer, butadiene-acrylonitrile copolymer, isobutylene polymer, isobutylene-butadiene copolymer, isobutylene-isoprene copolymer, acrylate polymer, ethylene-propylene copolymer, ethylene-propylene-diene copolymer Examples thereof include coalescence, thiocol rubber, polysulfide rubber, polyurethane rubber, polyether rubber (for example, polypropylene oxide), epichlorohydrin rubber and the like.

Furthermore, in order to impart conductivity to the inner layer, a conductive substance can be added to the inner layer. The conductive material added to the inner layer is preferably one that does not significantly change the properties of the thermoplastic resin. Examples of conductive materials include:
Examples thereof include carbon-based inorganic conductive powders and fibers such as carbon black particles, carbon fibers and carbon nanotubes.

Moreover, in the range which does not impair the effect of this invention with respect to the material of an inner layer,
Antioxidants, heat stabilizers, heat aging inhibitors, anti-mold agents, plasticizers, crystal nucleating agents, fluidity improvers, UV absorbers, lubricants, mold release agents, dyes, pigments and other colorants, flame retardants, difficult One or more additives such as a fuel aid may be added.

  Hereinafter, the present invention will be described in more detail based on examples.

First, physical property / characteristic evaluation / measurement methods are shown below.
-Refractive index measurement Measuring device: Spectroscopic ellipsometer (manufactured by Tokyo Instruments Inc., trade name: SpedEL-2000)
Measurement sample: A composition for an inner layer or an outermost layer was applied and placed on a glass substrate in advance, and surface transfer processing was performed so that the surface roughness Ra of the measurement surface was 0.05 μm or less.
Measurement value: An average value in a wavelength region of 830 to 870 nm was defined as a refractive index.

Thickness measurement (1) Inner layer thickness measurement Measuring device: Linear gauge (Ono Sokki Co., Ltd., trade name: HS-3412)
Measurement sample: Endless tube was cut.
Measurement value: Measured at a pitch of 10 mm in the tube cylinder direction, and the average value was taken as the thickness value.
Measurements were made at 30 locations on the inner layer of the endless belt, and the average value was taken as the thickness of the inner layer.
(2) Outermost layer thickness measurement Measuring device: Scanning electron microscope (manufactured by Hitachi High-Technologies Corporation, trade name: S-3400)
Measurement sample: The endless belt on which the outermost layer was arranged was cut in the cross-sectional direction and placed in an observation holder.
Measurement value: The thickness of the outermost layer was measured by observing the cross section of the endless belt.
Measurements were made at 30 locations on the outermost layer of the endless belt, and the average value was taken as the thickness of the outermost layer.

Infrared transmittance measurement Measuring device: Spectrophotometer (trade name: U4000, manufactured by Hitachi, Ltd.)
Measurement sample: The composition for forming the outermost layer was applied and placed in advance on a glass substrate, and surface transfer processing was performed so that the surface roughness Ra of the measurement surface was 0.05 μm or less.
Measurement value: The average value in the wavelength region of 830 to 870 nm was defined as the transmittance.

[Example 1]
-Inner layer As the composition for forming the inner layer, polyvinylidene fluoride (manufactured by Kureha Chemical Industry Co., Ltd., trade name: KF polymer) was used. In order to impart conductivity to this, a compound containing 8% by mass of acetylene black (trade name: Denka Black powder, manufactured by Denki Kagaku Kogyo Co., Ltd.) and polyvinylidene fluoride and an alkyl quaternary ammonium sulfate ( 10% by mass of (C ₄ H ₉ ) ₄ NHSO ₄ ) manufactured by Guangei Chemical Industry Co., Ltd. was added to polyvinylidene fluoride. These were kneaded using a kneading extruder having a twin screw under a nitrogen gas atmosphere to obtain pellets of a resin composition. The pellets were dried under a nitrogen gas atmosphere.
Next, pellets of this resin composition were supplied to a cylindrical extrusion device and melt extruded to obtain a cylindrical endless tube having a thickness of 100 μm.
The refractive index of this endless tube (inner layer) was 1.41.

-Outermost layer As the composition for forming the outermost layer, an ultraviolet curable acrylic resin (manufactured by JSR, trade name: Desolite Z7501) was used. In order to impart conductivity to this, 30% by mass of zinc antimonate isopropyl alcohol sol (manufactured by Nissan Chemical Co., Ltd., trade name: Celnax) was added to the acrylic resin. To this, 40% by mass of isopropyl alcohol with respect to the acrylic resin and 10% by mass of methyl ethyl ketone with respect to the acrylic resin were mixed and stirred. Furthermore, as an infrared absorber, a phthalocyanine compound (manufactured by Yamamoto Kasei Co., Ltd., trade name: YKR-2080) was added in an amount of 1.7% by mass with respect to the acrylic resin to obtain a solution of the composition for forming the outermost layer. Using this solution, it was applied to the outside of the inner layer endless tube using the dip coating method, and this was irradiated with ultraviolet rays to obtain an outermost layer having a thickness of 0.9 to 1.1 μm.
The refractive index of the outermost layer was 1.60, and the infrared transmittance was 38%.
The average regular reflectance of the surface of the outermost layer of the endless belt of this example was 5.1%, and the variation in regular reflectance was within ± 9%.

  The endless belt of this example was incorporated as a transfer material conveying belt of the image forming apparatus having the configuration shown in FIG. 1, and the color misregistration detection capability was confirmed. It was confirmed that the magnitude of the output signal from the color misregistration detecting means and the variation in the signal were small, and the color misregistration detection pattern made of toner disposed on the endless belt was stably detected. In this embodiment, an LED having an emission center wavelength of 860 nm is used as the light emitting element of the color misregistration detecting means.

[Example 2]
In the present embodiment, an endless belt is shown in which variation in regular reflectance on the surface of the outermost layer of the endless belt is further suppressed by making the infrared transmittance of the outermost layer of the endless belt lower than that in the first embodiment.

Inner layer The inner layer was formed in the same manner as in Example 1.

-Outermost layer As the composition for forming the outermost layer, an ultraviolet curable acrylic resin (manufactured by JSR, trade name: Desolite Z7501) is used. In order to impart conductivity to this, isopropyl alcohol sol of zinc antimonate (Nissan) 30% by mass (trade name: Celnax, manufactured by Kagaku Co., Ltd.) was added to the acrylic resin. To this, 30% by mass of isopropyl alcohol with respect to the acrylic resin and 20% by mass of methyl ethyl ketone with respect to the acrylic resin were mixed and stirred. Furthermore, as an infrared absorber, a phthalocyanine compound (manufactured by Yamamoto Kasei Co., Ltd., trade name: YKR-2080) is 2.2% by mass relative to the acrylic resin, and a phthalocyanine compound (manufactured by Nippon Shokubai Co., Ltd., trade name: EX-HA1). 0.7 mass% was added with respect to the acrylic resin, and the solution of the composition for outermost layer formation was obtained. Using this solution, it was applied to the outside of the inner layer endless tube using the dip coating method, and this was irradiated with ultraviolet rays to obtain an outermost layer having a thickness of 0.9 to 1.1 μm.
This outermost layer had a refractive index of 1.61 and an infrared transmittance of 23%.
The average regular reflectance of the surface of the outermost layer of the endless belt of this example was 5.1%, and the variation in regular reflectance was within ± 5%.

  The endless belt of this example was incorporated as a transfer material conveying belt of the image forming apparatus having the configuration shown in FIG. 1, and the color misregistration detection capability was confirmed. It was confirmed that the magnitude of the output signal from the color misregistration detection means and the signal variation were smaller than those in Example 1, and the color misregistration detection pattern made of toner arranged on the endless belt was stably detected. In this embodiment, an LED having an emission center wavelength of 860 nm is used as the light emitting element of the color misregistration detecting means.

Example 3
In this embodiment, an endless belt is shown in which the average regular reflectance of the surface of the outermost layer of the endless belt is higher than that of the first embodiment.

Inner layer The inner layer was formed in the same manner as in Example 1.

-Outermost layer After addition of the solvent of Example 2 (isopropyl alcohol and methyl ethyl ketone), 30% by mass of titania-based complex oxide methyl ethyl ketone sol (Catalyst Chemical Industries, trade name: Queen Titanic) was added to the acrylic resin. Stir. Then, the infrared rays absorber similar to Example 2 was added, and the solution of the composition for outermost layer formation was obtained. Using this solution, the outer layer of the inner layer was coated on the outer side using a dip coating method, and this was irradiated with ultraviolet rays to obtain an outermost layer having a thickness of 0.9 to 1.1 μm.
The refractive index of the outermost layer was 1.78, and the infrared transmittance was 21%.
The average regular reflectance of the surface of the outermost layer of the endless belt of this example was 5.5%, and the variation in regular reflectance was within ± 7%.

  The endless belt of this example was incorporated as a transfer material conveying belt of the image forming apparatus having the configuration shown in FIG. 1, and the color misregistration detection capability was confirmed. It was confirmed that the magnitude of the output signal from the color misregistration detection means was further improved as compared with Example 2, and the color misregistration detection pattern made of toner disposed on the endless belt was stably detected.

Example 4
In this embodiment, an endless belt is shown in which an elastomer layer is provided on the outer side (outermost layer side) of the resin layer (polyvinylidene fluoride layer) and on the inner side of the outermost layer.

-Inner layer For the composition for forming the inner layer, polyvinylidene fluoride (made by Kureha Chemical Industry Co., Ltd., trade name: KF polymer) is used, and acetylene black (made by Denki Kagaku Kogyo Co., Ltd., trade name) is used to impart conductivity. : Denka black powder) is a compound containing 8% by mass of polyvinylidene fluoride and a compound containing alkyl quaternary ammonium sulfate (Guangei Chemical Industry Co., Ltd., (C ₄ H ₉ ) ₄ NHSO ₄ ). 10 mass% was added with respect to. These were kneaded using a kneading extruder having a twin screw under a nitrogen gas atmosphere to obtain pellets of a resin composition. The pellets were dried under a nitrogen gas atmosphere.
Next, the pellets of the resin composition were supplied to a cylindrical extruder and melt extruded to obtain a cylindrical endless tube having a thickness of 100 μm.

On the other hand, acetylene black (made by Denki Kagaku Kogyo Co., Ltd., trade name: Denka Black powder) is heated to impart conductivity to the thermoplastic elastomer (made by AES Japan, trade name: Santoprene 8211-55). 9.5% by mass of the plastic elastomer was added and kneaded, and the resulting composition was extruded into a sheet shape to obtain a sheet having a thickness of 50 μm.
The thermoplastic elastomer composition sheet was formed into a cylindrical shape on the outside of the polyvinylidene fluoride endless tube to form an inner layer (layered inner layer) of the endless belt.
As a method for forming a sheet of a thermoplastic elastomer composition into a cylindrical shape outside the endless tube of polyvinylidene fluoride, the step of the joint of the sheet has no effect on the use of an endless belt for an image forming apparatus. Any method may be used as long as sufficient strength is ensured. As a method of forming a sheet-like plastic into a cylindrical shape, for example, a method of welding only both ends of the sheet described in JP-A-7-205274 can be mentioned. Moreover, it arrange | positions in the position which aligns the edge part of a sheet-like plastic between the two cylindrical metal molds which are described in patent 3441860 from which a thermal expansion coefficient differs, and the whole including a metal mold | die is heated, and is endless. A method for obtaining a belt can also be exemplified.
In this example, an inner layer was obtained by bonding a sheet of a thermoplastic elastomer composition to the outside of a polyvinylidene fluoride endless tube using the method described in Japanese Patent No. 3441860.
The refractive index of the laminated inner layer was 1.48.

-Outermost layer The outermost layer was formed in the same manner as in Example 1.
The average regular reflectance of the outermost surface of the endless belt of this example was 5.1%, and the variation in regular reflectance was within ± 7%.
The endless belt of this example was incorporated as a transfer material conveying belt of the image forming apparatus having the configuration shown in FIG. 1, and the color misregistration detection capability was confirmed. It was confirmed that the magnitude of the output signal from the color misregistration detecting means and the variation in the signal were small, and the color misregistration detection pattern made of toner disposed on the endless belt was stably detected.

[Comparative Example 1]
This comparative example shows an endless belt in which the regular reflectance of the outermost layer surface of the endless belt is smaller than that of the example.

Inner layer The inner layer was formed in the same manner as in Example 1.

-Outermost layer As the composition for forming the outermost layer, an ultraviolet curable acrylic resin (manufactured by JSR, trade name: Desolite Z7501) is used. Chemical Co., Ltd. (trade name: Cellnax) was added in an amount of 15% by mass to the acrylic resin. To this, 40% by mass of isopropyl alcohol with respect to the acrylic resin and 10% by mass of methyl ethyl ketone with respect to the acrylic resin were mixed and stirred. Furthermore, as an infrared absorber, a phthalocyanine compound (manufactured by Yamamoto Kasei Co., Ltd., trade name: YKR-2080) was added in an amount of 1.7% by mass with respect to the acrylic resin to obtain a solution of the composition for forming the outermost layer. Using this solution, it was applied to the outside of the inner layer endless tube using the dip coating method, and this was irradiated with ultraviolet rays to obtain an outermost layer having a thickness of 0.9 to 1.1 μm.
The refractive index of this outermost layer was 1.58, and the infrared transmittance was 40%.
The average regular reflectance of the surface of the outermost layer of the endless belt of this comparative example was 4.9%, and the variation in regular reflectance was within ± 4%.

  The endless belt of this comparative example is incorporated as a transfer material conveying belt of the image forming apparatus having the configuration shown in FIG. 1 and the color misregistration detection capability is confirmed. As a result, the output signal on the endless belt surface from the color misregistration detecting means is small. Therefore, it has been difficult to stably detect a color misregistration detection pattern made of toner disposed on an endless belt.

[Comparative Example 2]
In this comparative example, an endless belt having a large variation in regular reflectance on the surface of the outermost layer of the endless belt is shown.

Inner layer The inner layer was formed in the same manner as in Example 1.

-Outermost layer As the composition for forming the outermost layer, an ultraviolet curable acrylic resin (manufactured by JSR, trade name: Desolite Z7501) is used. In order to impart conductivity to this, isopropyl alcohol sol of zinc antimonate (Nissan) 30% by mass (trade name: Celnax, manufactured by Kagaku Co., Ltd.) was added to the acrylic resin. To this, 40% by mass of isopropyl alcohol with respect to the acrylic resin and 10% by mass of methyl ethyl ketone with respect to the acrylic resin were added and stirred to obtain a solution of the composition for forming the outermost layer. Using this solution, it was applied to the outside of the inner layer endless tube using the dip coating method, and this was irradiated with ultraviolet rays to obtain an outermost layer having a thickness of 0.9 to 1.1 μm.
The refractive index of this outermost layer was 1.61, and the infrared transmittance was 78%.
The average regular reflectance of the surface of the outermost layer of the endless belt of this comparative example was 5.1%, and the variation in regular reflectance was within ± 13%.
The variation in regular reflectance of this comparative example is that no infrared absorber is contained in the composition for forming the outermost layer, the infrared transmittance of the outermost layer is as large as 78%, and the outermost layer and the inner layer It is considered that the interference occurred at the interface because it was not uniform.

  The endless belt of this comparative example is incorporated as a transfer material conveying belt of the image forming apparatus having the configuration shown in FIG. 1 and the color misregistration detection capability is confirmed. It has been difficult to stably detect a color misregistration detection pattern made of the arranged toner.

[Comparative Example 3]
This comparative example also shows an endless belt having a large variation in regular reflectance on the outermost layer surface of the endless belt.

Inner layer The inner layer was formed in the same manner as in Example 1.

-Outermost layer As the composition for forming the outermost layer, an ultraviolet curable acrylic resin (manufactured by JSR, trade name: Desolite Z7501) is used. In order to impart conductivity to this, isopropyl alcohol sol of zinc antimonate (Nissan) Chemical Co., Ltd., trade name: CELNAX) was added in an amount of 15% by mass to the acrylic resin. To this, 30% by mass of isopropyl alcohol with respect to the acrylic resin and 20% by mass of methyl ethyl ketone with respect to the acrylic resin were added and stirred. Thereafter, 53% by mass of methyl ethyl ketone sol (trade name: Queen Titanic, manufactured by Catalyst Kasei Kogyo Co., Ltd.) of a titania-based composite oxide was added to the acrylic resin and stirred. Then, the infrared absorber similar to Example 1 was added, and the solution of the composition for outermost layer formation was obtained. Using this solution, it was applied to the outside of the inner layer endless tube using the dip coating method, and this was irradiated with ultraviolet rays to obtain an outermost layer having a thickness of 0.9 to 1.1 μm.
This outermost layer had a refractive index of 1.81 and an infrared transmittance of 25%.
The average regular reflectance of the surface of the outermost layer of the endless belt of this comparative example was 5.3%, and the variation in regular reflectance was within ± 12%.
As the refractive index of the outermost layer increases, the difference from the refractive index of the inner layer increases, and interference between the reflected light at the outermost layer surface and the reflected light at the interface between the outermost layer and the inner layer is amplified. It became clear that the variation in reflectance is a large value exceeding ± 10%.

  The endless belt of this comparative example is incorporated as a transfer material conveying belt of the image forming apparatus having the configuration shown in FIG. 1 and the color misregistration detection capability is confirmed. It has been difficult to stably detect a color misregistration detection pattern made of the arranged toner.

A summary of the examples and comparative examples is shown in Table 1.

1 is a diagram illustrating a schematic configuration of an image forming apparatus (color image forming apparatus) having a transfer material conveyance belt. 1 is a diagram illustrating a schematic configuration of an image forming apparatus (color image forming apparatus) having an intermediate transfer belt. It is a figure explaining a color shift detection means.

Explanation of symbols

1a photosensitive drum 1b photosensitive drum 1c photosensitive drum 1d photosensitive drum 2a charger 2b charger 2c charger 2d charger 3a laser scanner 3b laser scanner 3c laser scanner 3d laser scanner 4a developer 4b developer 4c developer 4d developer S transfer Material 5a Transfer roller 5b Transfer roller 5c Transfer roller 5d Transfer roller 6a Cleaner 6b Cleaner 6c Cleaner 6d Cleaner 7a Process cartridge 7b Process cartridge 7c Process cartridge 7d Process cartridge 9 Transfer material transport belt 10 Fixing device 11 Intermediate transfer belt 5pa Primary transfer roller 5pb Primary transfer roller 5pc Primary transfer roller 5pd Primary transfer roller 5s Secondary transfer roller 20 Color shift detection means 21 Light emitting element 22 Light reception Element 23 Color misregistration detection pattern 24 Light emission optical path 25 Light reception optical path

Claims (7)

  In an endless belt for an image forming apparatus having at least two layers of an inner layer and an outermost layer, the average regular reflectance of the surface of the outermost layer is 5.0% or more, and the variation in regular reflectance of the surface of the outermost layer is An endless belt for an image forming apparatus, which is within ± 10% of an average regular reflectance.   The endless belt for an image forming apparatus according to claim 1, wherein the outermost layer contains an infrared absorber, and the refractive index of the outermost layer is higher than the refractive index of the inner layer.   The endless belt for an image forming apparatus according to claim 1, wherein the outermost layer has a refractive index of 1.60 or more and 1.80 or less.   The endless belt for an image forming apparatus according to any one of claims 1 to 3, wherein an infrared transmittance of the outermost layer is 40% or less.   The endless belt for an image forming apparatus according to claim 1, wherein the outermost layer contains an acrylic resin as a binder resin.   The endless belt for an image forming apparatus according to any one of claims 1 to 5, wherein the inner layer contains a thermoplastic resin as a binder resin. An image forming apparatus comprising the endless belt for an image forming apparatus according to claim 1.

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