JP7576459B2 - Image forming apparatus belt and method for manufacturing same - Google Patents

Description

The present invention relates to a belt used in an image forming apparatus. More specifically, the present invention relates to an intermediate transfer belt that carries on its surface a toner image that has been primarily transferred onto a photoreceptor in an electrophotographic system and transports the image to an area where it is secondarily transferred onto a recording medium such as paper, a transfer transport belt that carries on its surface a recording medium onto which a toner image is transferred and transports the recording medium, and a paper transport belt that transports a recording medium such as paper in an inkjet system. The image forming apparatus belt of the present invention is particularly suitable for use in an image forming apparatus that utilizes an optical sensor.

A typical electrophotographic color image forming apparatus (such as a color printer or a color copier) has four process cartridges, one for yellow, one for magenta, one for cyan, and one for black. In each process cartridge, an electrostatic latent image is formed on a photoconductor based on image data separated into four colors, and toner is supplied onto the electrostatic latent image to form a toner image. In the intermediate transfer method, the four toner images are transferred in sequence onto an intermediate transfer belt, and after forming a color image on the belt, the toner images are transferred and fixed onto a recording medium such as paper. On the other hand, in the tandem method, the recording medium is transported to each process cartridge by a transfer transport belt, and the four toner images are transferred in sequence onto the recording medium and fixed thereon.
On the other hand, the inkjet method does not use a photoconductor, but instead forms an image by dropping ink directly onto a recording medium, which is then transported by a paper transport belt to one of four ink cartridges (yellow, magenta, cyan, and black) in sequence.

The intermediate transfer belt, transfer transport belt, and paper transport belt used here are cleaned by a cleaning unit when their surfaces become soiled with toner, ink, paper powder, etc., and the timing of this cleaning is measured by an optical sensor. Also, to prevent misalignment of the positional relationship of the four images (no color shift), the toner image on the intermediate transfer belt and the position of the recording medium on the transfer transport belt and paper transport belt are also measured by an optical sensor.
The optical sensor reflects light emitted from a light-emitting element on the belt surface, receives the reflected light with a light-receiving element, and measures the belt surface. In order to improve the accuracy of the optical sensor, it is required that the image forming device belt (1) has a large light reflection and (2) has a small variation in the light reflection. If the light reflection of the belt surface is small, the amount of change in the light reflection when toner or the like adheres to the belt is also small, making it difficult for the optical sensor to detect the adhesion of toner or the like. In addition, if the variation in the light reflection is large, the amount of light reflection changes even if toner or the like does not adhere to the belt, which may cause the cleaning unit or the like to malfunction.

In addition, belts for image forming apparatuses are also required to have good releasability of toner, etc. Furthermore, they are also required to have stain resistance, wear resistance, scratch resistance, etc. In order to impart these functions to belts for image forming apparatuses, coating agents having various functions are often applied thereto.
However, when the hardness of the coating layer is increased to improve scratch resistance, cracks are more likely to occur. When the thickness of the coating layer is reduced (1.5 μm or less) to prevent cracks, slight thickness unevenness in the coating layer causes interference fringes, which can change the amount of light reflection. When the amount of light reflection changes, it becomes difficult to control the optical sensor.

Patent Document 1 is an invention related to a belt for an image forming device (referred to as an "endless belt" in Patent Document 1) having high color shift detection performance. The belt for an image forming device is characterized in that the average regular reflectance of the surface layer (referred to as the "outermost layer" in Patent Document 1) is 5.0% or more, with the variation being within ±10% of the average regular reflectance. Patent Document 1 is characterized in that an infrared absorbing agent is contained in the surface layer in order to exhibit the performance.
Japanese Patent Application Laid-Open No. 2003-233633 relates to an invention relating to a transfer belt for an image forming apparatus that has small variations in intensity of reflected light from an optical sensor, and contains an oil-soluble dye such as an azo dye or an anthraquinone dye in a surface layer.

JP 2007-179013 A JP 2018-106036 A

The inventions described in Patent Documents 1 and 2 utilize an infrared absorbing agent or an oil-soluble dye (hereinafter collectively referred to as "light absorbing agent") to suppress interference between light emitted from the light emitting element of the optical sensor, reflected from the outermost surface of the surface layer, and light that passes through the surface layer and is reflected from the interface between the surface layer and the endless belt. However, in order to reliably suppress interference, it is necessary to add a large amount of light absorbing agent to the surface layer, which leads to a decrease in the scratch resistance of the belt.

The problem that this invention aims to solve is to provide a belt for an image forming device whose surface condition can be accurately measured by an optical sensor. More specifically, the objective is to provide a belt for an image forming device that (1) has high light reflection and (2) has small variation in light reflection.

As a result of intensive research aimed at solving the above problems, the inventors discovered that by setting the surface layer to a specific thickness range, the amount of light reflection can be increased and the variation in the amount of light reflection can be suppressed, leading to the invention.

That is, according to the present invention, there is provided a belt for an image-forming apparatus as described in the following items [1] to [4].
[1] A belt for an image-forming apparatus having a surface layer made of a cured resin on an endless belt, the surface layer having a thickness of 90 to 210 nm.
[2] The belt for an image-forming apparatus according to [1], wherein the resin cured product is a cured product of an ionizing radiation curable compound or a cured product of a thermosetting compound.
[3] The image-forming apparatus belt according to [2], wherein the resin cured product is a (meth)acrylic compound cured by ionizing radiation.
[4] The image-forming apparatus belt according to [3], wherein the (meth)acrylic compound is a urethane (meth)acrylate oligomer.

Further, the present invention provides a belt for an image forming apparatus according to any one of the above items [5] to [7].
[5] The image-forming apparatus belt according to [2], wherein the resin cured product is a urethane emulsion cured by heat.
[6] The image-forming apparatus belt according to any one of [1] to [5], wherein the endless belt is made of a resin composition containing a fluorine-based resin as a main component.
[7] The image-forming apparatus belt according to any one of [1] to [6], wherein the surface layer of the image-forming apparatus belt has a glossiness (incident angle 60°) of 90 or more.

Further provided is a transfer transport belt as described in [8], an image forming apparatus as described in [9], and a method for manufacturing a belt for an image forming apparatus as described in [10].
[8] A transfer/transport belt, comprising the belt for an image forming apparatus according to any one of [1] to [7].
[9] An image forming apparatus having the belt for image forming apparatus according to any one of [1] to [7].
[10] A method for manufacturing a belt for an image-forming apparatus according to any one of [1] to [7], characterized by comprising, in order, a belt-forming step of forming a cylindrical endless belt having a ten-point average roughness (Rz) of 0.3 to 1.4 μm as measured in accordance with JIS B0601-1982, a coating step of coating a surface of the endless belt with a coating agent obtained by diluting an ionizing radiation-curable compound with a solvent, or a coating agent obtained by diluting a thermosetting compound with water as necessary, and a curing step of drying the coating agent and then curing it with ionizing radiation or heat.

The image forming device belt of the present invention has a large amount of light reflection and little variation in the amount of light reflection, so there is little unevenness in glossiness, and even if the amount of light reflection changes slightly due to the influence of interference fringes, the surface condition can be accurately measured by an optical sensor. In addition, since the thickness of the surface layer is within a specific range, the surface layer is less likely to crack, and manufacturing costs are reduced. In addition, since no light absorbing agent is used, the image forming device belt has good abrasion resistance and low manufacturing costs.

In addition, when the surface layer is a product of an acrylic compound cured by ionizing radiation, or further a product of a urethane (meth)acrylate oligomer cured by ionizing radiation, the belt for an image forming apparatus can be easily imparted with functions such as slipperiness, water repellency, toner releasability, etc. Therefore, the belt can be suitably used for color printers which require colorization of images, high image quality, high speed, paper compatibility, etc.
Furthermore, when the surface layer is a product of a urethane emulsion cured by heat, folding resistance can be imparted to the image-forming apparatus belt.

Furthermore, when the endless belt is mainly composed of a fluorine-based resin, the belt for the image forming apparatus can be endowed with properties such as flame retardancy, chemical resistance, and bending resistance.
Furthermore, since the gloss of the image-forming belt according to the present invention exceeds 90, the surface can be easily measured by an optical sensor.
Furthermore, the image-forming apparatus belt of the present invention can be particularly effective when an endless belt having a ten-point average roughness (Rz) of 0.3 to 1.4 μm as measured in accordance with JIS B0601-1982 is used.

1 is a schematic perspective view illustrating an embodiment of a belt for an image-forming apparatus according to the present invention.

One embodiment of the present invention will be described below. Note that the following description is intended to provide a better understanding of the gist of the invention, and does not limit the present invention unless otherwise specified. In addition, the shapes and dimensions (length, width, etc.) of the configurations shown in the drawings in this application do not necessarily reflect the actual shapes and dimensions, and have been changed as appropriate to clarify and simplify the drawings.

Figure 1 is a schematic perspective view showing one embodiment of the image forming device belt of the present invention. The image forming device belt 1 of the present invention (hereinafter, abbreviated as "belt" as necessary) comprises a cylindrical endless belt 2 and a surface layer 3 covering the surface of the belt.

<Endless belt>
The material constituting the endless belt is not particularly limited, but is preferably made of a thermoplastic resin in consideration of moldability. For example, fluorine-based resin, polyamide-based resin, polyester-based resin, polycarbonate-based resin, polyamideimide-based resin, polyimide-based resin, etc. can be used alone, or in a blend of two or more types, or in a multi-layered form. Among these, fluorine-based resin is flame retardant by itself, unlike other resins, and is easy to extrude, and also has antifouling and releasability, so it is optimal for the endless belt of the image forming device belt. As such fluorine-based resin, polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, ethylene-tetrafluoroethylene copolymer, polyhexafluoropropylene, ethylene-vinylidene fluoride copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer, etc. can be used.

In recent years, with the increasing speed of printers and the like, a high elastic modulus is required for the endless belt. If the elastic modulus is low, the belt may stretch during driving, causing the transfer position to shift. The tensile elastic modulus of the endless belt is preferably 700 MPa or more, and more preferably 1,000 MPa or more. In order to increase the tensile elastic modulus of the endless belt, a reinforcing material such as a flat filler or whiskers may be added to the above-mentioned thermoplastic resin. The thickness of the endless belt is preferably 50 to 300 μm, and particularly preferably 75 to 200 μm. If the thickness is 50 μm or less, it is difficult to obtain sufficient tensile strength, and if the thickness exceeds 300 μm, the flexibility deteriorates.

When the image forming apparatus belt of the present invention is used as a transfer belt such as an intermediate transfer belt or a transfer conveyor belt, the volume resistivity is preferably 10 ⁵ to 10 ¹³ Ω·cm, and particularly preferably 10 ⁷ to 10 ¹² Ω·cm. In order to control the volume resistivity of the transfer belt within the above range, a conductive material can be blended into the endless belt within a range that does not impede the object of the present invention. The conductive material includes an electronically conductive material and an ionically conductive material.

Examples of the electron conductive material include carbon-based materials such as carbon black, graphite, and carbon nanotubes; conductive polymers such as polyaniline, polythiophene, and polyacetylene; and conductive inorganic particles such as inorganic particles that have been surface-treated with aluminum zinc oxide, antimony tin oxide, indium tin oxide, and carbon black.
Examples of ion-conductive materials include polyetheresteramide, polyetherester, polyetheramide, polyethylene oxide, polyethylene oxide copolymer, partially cross-linked polyethylene oxide copolymer, ionic electrolytes, etc., which can be used alone or in combination of two or more. As the ionic electrolyte, alkali metal thiocyanate, phosphate, sulfate, halogen-containing oxyacid salt, and tetraalkylammonium salt can be used alone or in combination of two or more. Among these, lithium perchlorate, sodium perchlorate, potassium perchlorate, lithium thiocyanate, sodium thiocyanate, and potassium thiocyanate are preferred.

<Surface layer>
The surface layer 3 of the belt 1 of the present invention is made of a cured resin and has a thickness of 90 to 210 nm, preferably 110 to 190 mm. If the thickness of the surface layer is less than 90 nm or more than 210 nm, the amount of light reflection of the surface layer decreases or the variation in light reflection increases, making it difficult to measure the belt surface with an optical sensor.

In consideration of the formability of the surface layer, the cured resin constituting the surface layer of the present invention is preferably a cured product of an ionizing radiation curable compound or a cured product of a thermosetting compound.
The ionizing radiation curable compound is not particularly limited as long as it is a compound that is cured by ionizing radiation, and may be an epoxy compound, a mixture of an epoxy compound and an oxetane compound, an acrylic compound, or the like. In the present invention, an ionizing radiation curable acrylic compound is particularly preferred. Among these, a urethane (meth)acrylate oligomer is particularly preferred. Here, (meth)acrylic means acrylic or methacrylic.
Urethane (meth)acrylate is a compound having an acrylic group and a urethane bond in the molecule, which is obtained by reacting a polyisocyanate with short-chain and long-chain polyols, and a hydroxyl group-containing (meth)acrylate such as hydroxy (meth)acrylate.

Examples of polyisocyanates include toluylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, and hydrogenated xylylene diisocyanate. Examples of short-chain polyols include glycerin, pentaerythritol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol. Examples of long-chain polyols include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polycaprolactone diol, polycarbonate diol, and polyester polyols obtained by reacting a short-chain diol with a dicarboxylic acid such as succinic acid or adipic acid. Examples of hydroxyl group-containing (meth)acrylates include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxybutyl (meth)acrylate.
In the present invention, polymerizable acrylic compounds other than the above-mentioned urethane (meth)acrylates can be used in combination.

The thermosetting compound is not particularly limited as long as it is a compound that is cured by heat, but a urethane emulsion in which a urethane resin is dispersed in water can be preferably used. Since the urethane resin shows flexibility, if the surface layer is made of a urethane resin, the belt for the image forming device has excellent folding resistance. The urethane resin is a reaction product of the above-mentioned polyisocyanate and polyol.
As the thermosetting compound of the present invention, an emulsion of a reaction product of a polyisocyanate and a carbonate-based polyol (carbonate-based urethane resin) is particularly preferred. The carbonate-based urethane resin has high toughness and good scratch resistance compared to urethane resins made of other polyols.

Furthermore, the surface layer may contain various additives such as water repellents, fillers, leveling agents, conductive agents, photosensitizers, stabilizers, polymerization inhibitors, defoamers, anti-sagging agents, adhesion improvers, modifiers, and plasticizers.

The water repellent can be selected as needed, but silicone-based water repellents and fluorine-based water repellents can be preferably used. As the silicone-based water repellent, a compound having a siloxane bond with a molecular weight of 500 or more is preferably used. Specifically, dimethylpolysiloxane having hydroxyl groups at both ends, alkylpolysiloxane having alkyl groups at the ends, alkoxy-modified dimethylpolysiloxane, fluoroalkyl-modified dimethylsilicone, etc. are mentioned. Furthermore, dimethylpolysiloxane having (meth)acrylic groups at the ends is preferable because it can maintain its effect for a long period of time because it is incorporated into the crosslinked structure via chemical bonds when the polymerizable acrylic compound hardens. When an ionizing radiation-curable acrylic coating agent containing these water repellents is applied and hardened to form a surface layer, the surface free energy of the belt surface is reduced, making it difficult for toner to adhere and reducing friction. Therefore, the releasability between the image forming device belt and the toner is improved, and the transfer efficiency is improved.

The surface layer of the present invention may contain a filler to impart scratch resistance to the image forming apparatus belt. Although there are no limitations on the particle size of the filler, taking into consideration dispersibility and the surface roughness of the resulting belt, it is preferable that the particle size is 0.02 μm or more and less than the thickness of the surface layer, and particularly 0.05 to 0.1 μm is preferable. These fillers may be surface-treated for the purpose of improving dispersibility within a range that does not impair slipperiness. A dispersant can also be used within a range that does not impair the characteristics of the belt. The amount of filler to be blended is preferably 0.5 to 40 parts by weight, particularly 1.0 to 30 parts by weight, per 100 parts by weight of the ionizing radiation curable compound or the heat curable compound.

Examples of fillers include fluororubber, graphite, fluorocarbon in which fluorine is bonded to graphite, powders of fluorine-containing resins such as polytetrafluoroethylene, polyvinylidene fluoride, ethylene-tetrafluoroethylene copolymer, and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer; silicone powders such as silicone resin, silicone rubber, and silicone elastomer; resin powders such as polyethylene, polypropylene, polystyrene, acrylic resin, nylon resin, phenolic resin, and epoxy resin; and inorganic powders such as silica, alumina, titanium oxide, and magnesium oxide. These fillers may be surface-treated to improve dispersibility in the coating agent, and may be used alone or in combination.

<Image forming device belt>
The surface layer of the image forming apparatus belt of the present invention preferably has a glossiness (incident angle 60°) of 90 or more, more preferably 95 or more. If the glossiness is less than 90, the amount of light reflected by the surface layer is small, and the amount of change in light reflection when toner or the like adheres is also small, making it difficult for an optical sensor to detect adhesion of toner, etc. The glossiness of the surface layer of the belt of the present invention is determined by the average value of values measured at three different points (total of 12 points) in the length direction in an area obtained by dividing the belt into four areas at equal intervals in the circumferential direction.
Furthermore, in the belt of the present invention, the difference between the maximum and minimum values measured at the above 12 points is preferably 12 or less, more preferably 10 or less, and even more preferably 8 or less. If the difference in gloss exceeds 12, the variation in light reflection becomes large, and even if no toner or the like is attached, the amount of light reflection changes, which may cause a cleaning unit or the like to malfunction.

<Method of Manufacturing Image-Forming Apparatus Belt>
The method for producing a belt of the present invention includes, in order, (1) a belt forming step of forming a cylindrical endless belt, (2) a coating step of applying a coating agent obtained by diluting an ionizing radiation curable compound with a solvent or a coating agent obtained by diluting a thermosetting compound with water as necessary onto a surface of the endless belt, and (3) a curing step of drying the coating agent and then curing it with ionizing radiation or heat.

(1) Belt molding process The resin for molding the endless belt described above is molded into the shape of an endless belt as shown in Fig. 1 by extrusion molding, centrifugal molding, dipping, etc. As a molding method that allows for relatively simple continuous production, the present invention proposes an extrusion molding method using an extruder equipped with an annular die. By this method, the resin is extruded from the annular die into a tubular shape, and the obtained tube is cut to a predetermined length to obtain an endless belt.

In addition, an endless belt using a circular die has an inherent problem that if the ten-point average roughness (Rz) measured in accordance with JIS B0601-1982 is relatively small, when a surface layer is provided on the surface of the endless belt, unevenness in glossiness is likely to occur. The present invention can be effective when used with an endless belt having a ten-point average roughness (Rz) of 0.3 to 1.4 μm, particularly 0.4 to 0.8 μm. In addition, the present invention can be effective with an endless belt having an arithmetic average roughness (Ra) measured in accordance with JIS B0601-1982 of 0.05 to 0.2 μm, particularly 0.05 to 0.15 μm, and further 0.06 to 0.12 μm.
The ten-point average roughness (Rz), arithmetic mean roughness (Ra) and maximum height (Rmax) in the present invention are all average values measured at any five points on the belt surface using a Surfcom 570A (manufactured by Tokyo Seimitsu Co., Ltd.) The values are measured using a stylus with a tip curvature radius of 2 μm, with a cutoff value of 0.8 mm, a measurement length of 2.5 mm and a speed of 0.3 mm/sec.

(2) Coating Step Prior to the coating step, a coating liquid is prepared.
Specifically, when the above-mentioned resin cured product is (i) a cured product of an ionizing radiation curable compound, the ionizing radiation curable compound, various additives, fillers, and the like which are blended as necessary, and a photopolymerization initiator for curing the ionizing radiation curable compound by ionizing radiation are diluted with a solvent to prepare a coating liquid.

Examples of photopolymerization initiators include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isobutyl ether, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyl dimethyl ketal, 1-hydroxycyclohexyl-phenyl ketone, 2-methyl-2-morpholino(4-thiomethylphenyl)propan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenyl ether, Examples include thoxyphosphine oxide, benzophenone, methyl o-benzoylbenzoate, hydroxybenzophenone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 2,4,6-tris(trichloromethyl)-S-triazine, 2-methyl-4,6-bis(trichloro)-S-triazine, 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-S-triazine, iron-arene complexes, and titanocene compounds. It is preferable to use one or more of these in combination.

The amount of solvent can be adjusted as appropriate depending on the desired viscosity of the coating agent, coating thickness, etc. For example, the amount of solvent is 70 to 2000 parts by weight, preferably 300 to 1500 parts by weight, per 100 parts by weight of the polymerizable compound in the ionizing radiation curable compound. If the amount of solvent is less than 70 parts by weight, the coating properties and handling properties will deteriorate, and it will be difficult to make the surface layer thin. If the amount of solvent exceeds 2000 parts by weight, drying will take a long time. The viscosity of the coating agent is desirably 50 mPa·s or less in order to obtain a thin surface layer with little change in thickness.

In addition, when the above-mentioned resin cured product is (ii) a product cured by heat of a urethane-based emulsion, a coating liquid can be obtained by mixing a urethane resin, water, and an emulsifier to prepare a urethane-based emulsion, and then diluting the emulsion by adding more water as necessary. The viscosity of the coating agent is preferably 200 mPa·s or less in order to obtain a thin surface layer with little change in film thickness.
Emulsions include forced emulsification type, which uses a surfactant as an emulsifier, and self-emulsification type, which introduces a hydrophilic group into the resin. The urethane-based emulsion of the present invention is preferably a self-emulsification type emulsion, which does not have the risk of the surfactant bleeding out after drying. The hydrophilic group of the self-emulsification type may be anionic, cationic, or nonionic.

Examples of methods for applying the coating agent to the surface of the endless belt include roll coating, bar coating, dip coating, spray coating, etc. Among these, the spray coating method is particularly suitable as the coating method of the present invention because it has excellent film thickness uniformity, and the roll coating method has little loss of coating agent.

(3) Curing step After the coating agent is applied onto the endless belt, the coating agent is dried and the surface layer is cured by ionizing radiation or heat, completing the belt of the present invention. The ionizing radiation in the present invention is not particularly limited, and examples thereof include ultraviolet rays, electron beams, alpha rays, beta rays, gamma rays, X-rays, and neutron rays. The dose of ultraviolet rays is usually 100 to 15,000 mJ/cm2, and preferably 300 to 8,000 mJ/cm2.
Furthermore, when the resin is cured by irradiation with ionizing radiation, it is not necessary to heat the resin to a high temperature as in the case of curing the resin by heat, and this has the advantage that the transfer belt for the image forming apparatus is not damaged by heat.

The effects of the present invention will be described in more detail below with reference to examples. The image-forming apparatus belts produced in the examples and comparative examples were evaluated for the following items. The results are shown in Table 1.
<Glossiness>
The glossiness was measured using a glossmeter Gloss Checker IG-320 manufactured by Horiba, Ltd., with the incident angle set to 60° and the receiving angle set to 60°. The belt was divided into four regions at equal intervals in the circumferential direction, and the measurement was performed at three different points in the longitudinal direction (12 points in total).

Example 1
100 parts by weight of polyvinylidene fluoride (having a tensile modulus of elasticity of 1,400 MPa) was mixed with 5 parts by weight of polyethylene oxide copolymer and 0.5 parts by weight of lithium perchlorate, kneaded in a twin-screw kneader, and pelletized to obtain a resin composition for an endless belt.
Using an extruder with a cylinder diameter of 50 mm and an annular die attached to the tip, the resin composition for the endless belt was extruded and molded into a tube shape, which was then cut to a length of 400 mm to prepare an endless belt with a thickness of 100 μm, a circumference of 850 mm, and a width of 400 mm.
The surface roughness of the endless belt was measured using a Surfcom 570A (Tokyo Seimitsu Co., Ltd.) in accordance with JIS B0601-1982, with a stylus tip radius of 2 μm, a cutoff value of 0.8 mm, a measurement length of 2.5 mm, and a speed of 0.3 mm/sec. Measurements were taken at five points on the endless belt surface, and the average values were found to be Ra=0.08 μm, Rmax=0.90 μm, and Rz=0.57 μm.

Next, 97 parts by weight of a urethane acrylate oligomer (manufactured by Negami Chemical Industries Co., Ltd.) having a molecular weight of 70,000 and a molecular weight per (meth)acrylic group (hereinafter referred to as a (meth)acrylic equivalent) of 1,380 as an ionizing radiation curable acrylic compound, 2.85 parts by weight of 2-hydroxy-2-methyl-1-phenyl-propan-1-one as a photopolymerization initiator, 0.15 parts by weight of a silicone-based water repellent, and 1,000 parts by weight of methyl isobutyl ketone as a solvent were added and dissolved uniformly to prepare a coating agent containing an ionizing radiation curable acrylic compound for the surface layer.
The obtained coating agent was applied to the surface of the endless belt by roll coating, and after drying, it was irradiated with ultraviolet light at 3,000 mJ/ ^cm2 to form a surface layer with a thickness of 110 nm. Then, it was cut to a width of 350 mm to obtain the image forming apparatus belt of Example 1. The evaluation results of the belt are shown in Table 1.

(Examples 2 to 4, Comparative Examples 1 to 6)
Belts were obtained in the same manner as in Example 1, except that the thickness of the surface layer was changed as shown in Table 1. The evaluation results of each belt are shown in Table 1.

The belts of Examples 1 to 3 had an average gloss value exceeding 90, and had a large amount of light reflection. In addition, the difference between the maximum and minimum gloss values was less than 10, and the variation in the amount of light reflection was small. Therefore, the surface condition can be accurately measured by the optical sensor. The belts of Comparative Examples 1 to 3 and 5 had an average gloss value less than 90, and therefore had a small amount of light reflection. Although the belts of Comparative Examples 4 and 6 had an average gloss value exceeding 90, the difference in gloss value was large, and the variation in the amount of light reflection was large.

1 Image forming apparatus belt 2 Endless belt 3 Surface layer

Claims (9)

A belt for an image forming apparatus having a surface layer made of a cured resin on an endless belt, the surface layer having a thickness of 90 to 210 nm,
The resin cured product is a (meth)acrylic compound cured by ionizing radiation,
The cured resin does not contain an oil-soluble dye,
The image-forming apparatus belt according to claim 1, wherein the surface layer of the image-forming apparatus belt has a glossiness (incident angle: 60°) of 90 or more . 2. The image-forming apparatus belt according to claim 1, wherein the (meth)acrylic compound is a urethane (meth)acrylate oligomer. 3. The image-forming apparatus belt according to claim 1, wherein the endless belt is made of a resin composition containing a fluorine-based resin as a main component. 4. The image forming apparatus belt according to claim 1, wherein the endless belt has a ten-point average roughness (Rz) of 0.3 to 1.4 μm as measured in accordance with JIS B0601-1982. 5. The image-forming apparatus belt according to claim 1, wherein the endless belt has an arithmetic mean roughness (Ra) of 0.05 to 0.2 μm as measured in accordance with JIS B0601-1982. 6. The belt for an image forming apparatus according to claim 1, which is used in an image forming apparatus utilizing an optical sensor. A transfer/transport belt, comprising the belt for an image forming apparatus according to any one of claims 1 to 5. 6. An image forming apparatus comprising the belt for image forming apparatus according to claim 1. a belt forming step of forming a cylindrical endless belt having a ten-point average roughness (Rz) of 0.3 to 1.4 μm as measured in accordance with JIS B0601-1982;
a coating step of coating a coating agent obtained by diluting an ionizing radiation curable compound with a solvent onto a surface of the endless belt;
a curing step of drying the coating agent and then curing the coating agent with ionizing radiation;
7. The method for manufacturing a belt for an image-forming apparatus according to claim 1, further comprising the steps of:

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